Is it prescribed to praise Allah after burping and to seek refuge with Him after yawning?

Praise
be to Allah

Firstly: 

Burping refers to the emission of air from the stomach with a
sound via the mouth when one is full. 

There is nothing in the Sunnah to indicate that it is
mustahabb for the Muslim, if he burps, to praise Allah or ask His
forgiveness or remember Him with any dhikr. A man burped in the presence of
the Prophet (blessings and peace of Allah be upon him) and he did not
instruct him to say any kind of dhikr (remembering Allah, may He be exalted)
after burping. 

At-Tirmidhi (2478) narrated – and classed the report as hasan
– that Ibn ‘Umar said: A man burped in the presence of the Prophet
(blessings and peace of Allah be upon him) and he said: “Keep your burps
away from us, for the one who eats his fill the most in this world will be
hungry for the longest time on the Day of Resurrection.” It was also classed
as hasan by al-Albaani in Saheeh at-Tirmidhi.

Burping results from eating too much, and eating too much is
regarded as blameworthy according to Islamic teaching. 

Al-Minnaawi (may Allah have mercy on him) said: That is
because the one who eats too much will drink too much, then he will sleep
too much, so his body will become lazy. End quote. 

At-Tayseer
(1/312) 

The Messenger (blessings and peace of Allah be upon him) told
that man not to burp in the presence of others, because this is offensive to
them and is contrary to good manners, and he encouraged that man to eat
less. 

But he did not encourage him to recite a particular dhikr, or
instruct him to ask Allah for forgiveness or to do anything else, which
indicates that reciting any dhikr after burping is not part of the Sunnah. 

Secondly: 

With regard to saying “al-hamdu Lillah (praise be to Allah)”
after burping, it depends: 

1.

If a person says that, believing that it is Sunnah and is an
act of worship that will bring him closer to Allah, then this comes under
the heading of innovation, because he is seeking to draw close to Allah by
means of something that He did not prescribe. 

2.

If he says that as a habit, without believing that it has any
particular virtue, then this is not described as being either Sunnah or
bid‘ah; rather it comes under the heading of permissible matters. 

3.

If he says it because of an idea that is established in his
mind, which is that burping results from having eaten one’s fill, which is a
blessing for which Allah deserves to be praised – and by the same token, if
a person yawns and remembers that this yawning comes from the Shaytaan, so
he seeks refuge with Allah from him, but he does not believe that this is
prescribed as a Sunnah; rather he says it because of the idea that is
established in his mind, 

Then in this case, it is more appropriate to say that there
is nothing wrong with it. 

These details concerning these three scenarios are a summary
of what our Shaykh, ‘Abd ar-Rahmaan al-Barraak (may Allah preserve him) told
us after this question was put to him. 

Ibn Muflih said:

The one who burps does not have to respond with anything. So
if he says, “Al-hamdu Lillah,” it may be said to him: “Hanee’an maree’an
(May the food be delightful and pleasant for you)” or “Hanna’aka Allahu wa
amraak (May Allah cause you to have the delight and pleasure of the food).”
This was stated in ar-Ri‘aayah al-Kubra and by Ibn Tameem, and
also by Ibn ‘Aqeel. And he said: We do not know of any Sunnah concerning
that; rather it is a made-up custom.

End quote from al-Aadaab ash-Shar‘iyyah (2/346) 

Shaykh ‘Abd al-Muhsin al-‘Abbaad was asked: What is the
ruling when one burps? 

He said: There is no report to indicate anything. But if a
person praises Allah in all situations, and praises Him for having eaten his
fill, which is one of the blessings of Allah, may He be glorified and
exalted, there is nothing wrong with that. But if he believes that this is
something that is prescribed in Islam in this situation, there is nothing to
indicate that as far as I know.

End quote from Sharh Sunan Abi Dawood (492/19). 

Among the fatwas of the scholars, there is a fatwa on the
issue of seeking refuge with Allah after yawning, which is similar to the
case under discussion here. 

In Fataawa al-Lajnah ad-Daa’imah (2/320), in a fatwa
issued by a committee under the leadership of Shaykh Ibn Baaz, it says: 

Seeking refuge with Allah after yawning was not mentioned in
any report at all. Rather the individual should try to suppress yawning as
much as he can, but if he seeks refuge with Allah from the Shaytaan when
yawning, during prayer or otherwise, there is nothing wrong with that. End
quote. 

Shaykh Ibn Baaz (may Allah have mercy on him) was asked: what
is the ruling on seeking refuge with Allah when yawning? Is there any
evidence concerning that? 

He said: There is nothing wrong with it, because yawning
comes from the Shaytaan. But there is no report to indicate that doing so is
mustahabb. However the Prophet (blessings and peace of Allah be upon him)
told us that “yawning is from the Shaytaan, so if one of you feels the urge
to yawn, let him suppress it as much as he can.” According to another
version, “let him place his hand over his mouth.” This indicates that it is
from the Shaytaan. 

If he says “A‘oodhu Billaahi min ash-Shaytaan ir-rajeem
(I seek refuge with Allah from the accursed Shaytaan),” there is nothing
wrong with that, but there is no report to this effect from the Prophet
(blessings and peace of Allah be upon him). 

http://www.binbaz.org.sa/mat/9357 

He also said: 

Many of the common folk do that because they know that this
is from the Shaytaan, and that is why they do it. Otherwise, we do not know
of anything in the Sunnah concerning that. Undoubtedly yawning is from the
Shaytaan, and when a believer feels lazy, or when something harmful happens
to him from the enemy of Allah, it is prescribed for him to seek refuge with
Allah from the accursed Shaytaan, and to remember Allah a great deal, and to
send blessings upon the Prophet (blessings and peace of Allah be upon him).
But we do not know of any specific report concerning this issue. But if he
seeks refuge with Allah from the Shaytaan when yawning because he knows that
it is from the Shaytaan, there is nothing wrong with that. However, we do
not say that it is Sunnah because there is no evidence to that effect. 

http://www.binbaz.org.sa/mat/9414

Shaykh ‘Abd al-Muhsin al-‘Abbaad said:

If a person seeks refuge with Allah from the Shaytaan on the
grounds that yawning is from the Shaytaan, although he does not believe that
this is a Sunnah of the Messenger of Allah (blessings and peace of Allah be
upon him), then there is nothing wrong with that. But if he believes that
this is Sunnah or thinks that it is prescribed for a person to say such and
such when yawning, this is not correct. But if he remembers that yawning is
from the Shaytaan, so he seeks refuge with Allah from the Shaytaan because
of that, without believing that this is Sunnah, there is nothing wrong with
that.

End quote from Sharh Sunan Abi Dawood (492/17)

And Allah knows best.