Intercourse during Ramadaan

Firstly: 

Intercourse during the day in Ramadaan is haraam for men and
women alike, who are obliged to fast during the day. Doing that is a sin for
which expiation (kafaarah) must be offered. The kafaarah is to free a slave;
if that is not possible then the person must fast for two consecutive
months; whoever is not able to do that must feed sixty poor persons. 

It was narrated that Abu Hurayrah (may Allaah be pleased with
him) said: Whilst we were sitting with the Prophet (peace and blessings
of Allaah be upon him), a man came to him and said, “O Messenger of Allaah,
I am doomed!” He said, “What happened?” He said, “I had intercourse with my
wife when I was fasting [in Ramadaan].” The Messenger of Allaah (peace
and blessings of Allaah be upon him) said, “Are you able to free a slave?”
He said, “No.” He said, “Are you able to fast for two consecutive months?”
He said, “No.” He said, “Can you feed sixty poor persons?” He said, “No.”
Then the Prophet (peace and blessings of Allaah be upon him) remained
silent for a while, and whilst we were like that, a large vessel of dates
was brought to the Prophet (peace and blessings of Allaah be upon him),
and he said, “Where is the one who was asking?” He said, “Here I am.” He
said, “Take these and give them in charity.” The man said, “Is there anyone
more poor than me, O Messenger of Allaah? For there is no household between
the two harrahs (lava fields – i.e., in Madeenah) that is poorer than my
household.” The Messenger of Allaah (peace and blessings of Allaah be
upon him) smiled until his eyeteeth could be seen, then he said, “Feed it to
your family.” 

(Narrated by al-Bukhaari, 1834, 1835; Muslim, 1111) 

Secondly: 

With regard to intercourse during the night in Ramadaan, this
is permitted and is not forbidden, and the time when it is permitted lasts
until the onset of dawn. When dawn comes, intercourse becomes forbidden. 

Allaah says (interpretation of the meaning): 

“It is made lawful for
you to have sexual relations with your wives on the night of As-Sawm (the
fasts). They are Libaas [i.e. body-cover, or screen, or Sakan (i.e. you
enjoy the pleasure of living with them] for you and you are the same for
them. Allaah knows that you used to deceive yourselves, so He turned to you
(accepted your repentance) and forgave you. So now have sexual relations
with them and seek that which Allaah has ordained for you (offspring), and
eat and drink until the white thread (light) of dawn appears to you distinct
from the black thread (darkness of night), then complete your Sawm (fast)
till the nightfall”

[al-Baqarah 2:187] 

This verse clearly states that it is permissible to eat,
drink and have intercourse during the nights of Ramadaan until dawn. 

After having intercourse it is obligatory to do ghusl, then
pray Fajr. 

And Allaah knows best.