The duaa' that is to be said before having intercourse is prescribed for the man, but there is nothing wrong with the woman saying it. See the answer to question no. 95742
It is Sunnah for the man, if he has intercourse with his wife and wants to do it a second time, to do wudoo' in between, and if he does ghusl, that is more proper.
It was narrated that Abu Saeed al-Khudri (may Allah be pleased with him) said: The Messenger of Allah (blessings and peace of Allah be upon him) said: If one of you has intercourse his wife and wants to repeat it, let him do wudoo' in between. Narrated by Muslim, 466. According to a report narrated by Ahmad (10795): Wudoo' as for prayer. Its isnaad was classed as saheeh by Shuayb al-Arna'oot in his commentary on Musnad al-Imam Ahmad, 3/28
Shaykh Ibn Uthaymeen (may Allah have mercy on him) was asked: If a man has intercourse with his wife and wants to do it a second time, what should he do?
In this case there are three levels:
(i) Doing ghusl before doing it again, and this is the highest level
(ii) Doing wudoo' only before doing it again, and this is of lesser status than the first
(iii) Not doing anything, neither ghusl nor wudoo'; this is the lowest level, but it is permissible.
But what should be noted is that they should not sleep without having purified themselves by either wudoo' or ghusl.
End quote from Majmoo al-Fataawa, 11/157
This Sunnah applies specifically to the man, because it is addressed to him, as it says in the hadeeth of Abu Saeed (may Allah be pleased with him) quoted above.
The scholars of the Standing Committee for Issuing Fatwas were asked (19/350):
The Prophet (peace be upon him) said: If one of you wants to go back to his wife (and have intercourse a second time), let him do wudoo'. Does this ruling apply to the man only, or does it also apply to the woman?
They replied: Wudoo' is prescribed when wanting to have intercourse again for the man, because he is the one who was instructed to do that, not the woman. End quote.
Al-Lajnah ad-Daa'imah li'l-Buhooth al-Ilmiyyah wa'l-Ifta.
Reproduced from Islam QA