When I was a teenager I used to masturbate sometimes during the day in Ramadaan, but I did not let the semen come out of the penis because I blocked it, but I still reached climax.

 What is the ruling on my fast, and how can I expiate for this grave sin? Please note that I do not know how many days I did this.


Praise be to Allaah.
 

It should be noted that this habit is haraam according to
sharee’ah, as is indicated in the Book of Allaah and the Sunnah of His
Prophet (peace and blessings of Allaah be upon him). We have already
quoted the evidence in detail in question no
329. This habit is
something that is repulsive to sound human nature and reason, and it is not
befitting for a Muslim to lower himself to this level. 

It should also be noted that sin has negative consequences a
person, in this world and in the Hereafter, if he does not repent and if
Allaah does not bestow His mercy upon him. We have already discussed this in
the following questions:
23425,
8861,
45040. 

With regard to the ruling on the matter mentioned in the
question, if you engaged in the secret habit but no semen came out as a
result, then the fast is not invalidated, according to the most sound
scholarly opinion, because what matters is the emission of semen. If it did
come out then the fast was invalidated and it has to be made up. If it did
not come out then the fast is not invalidated. But whatever the case you
have to repent to Allaah and seek His forgiveness for wasting the fast by
doing such things. 

Semen may be emitted a short while later even if you
prevented it from coming out. In that case the fast of that day is
invalidated and you have to make it up. If you do not know how many days
your fast was invalidated, then try to work it out until you reach a figure
you think is most likely, then make up the days that you owe. 

Shaykh Ibn ‘Uthaymeen said in Sharh Zaad al-Mustaqni’:
Is it possible for semen to move without being emitted? 

Yes, that is possible,
when a person’s desire subsides for some reason, then semen does not come
out. 

And they gave another example: if a person holds his penis so
that no semen comes out. Even though the fuqaha’ gave this as an example, it
is very harmful. The fuqaha’ (may Allaah have mercy on them) gave something
as an example regardless of how harmful or not it may be. But usually in
such cases the semen is released after the person lets go of his penis. 

Some of the scholars said that ghusl is not required if the
semen moves. This is the view favoured by Shaykh al-Islam and is the correct
view. The  evidence for that is as follows:  

1 – The hadeeth of Umm Salamah in which it says: “Yes, if she
sees water.” He did not say, If she feels it moving. If ghusl were required
when it moves, then he (peace and blessings of Allaah be upon him)
would have pointed it out because there would have been a need to do so. 

2 – The hadeeth of Abu Sa’eed al-Khudri: “Water is for
water.” In this case there is no water (i.e., emission). So this hadeeth
indicates that if there is no water (emission) there is no need for water
(ghusl). 

3 – The basic principle is that the person remains pure
(taahir) and no ghusl is required. This principle cannot be changed unless
there is evidence to that effect. 

Al-Sharh al-Mumti’, 1/280 

See also: al-Furoo’, 1/197; al-Mabsoot, 1/67;
al-Mughni, 1/128; al-Majmoo’, 2/159; al-Mawsoo’ah
al-Fiqhiyyah al-Kuwaitiyyah, 4/99 

See also questions no.
38074 and
2571. 

And Allaah knows best.