it is allowed for him to enjoy pleasure with his wife in any way except for her private parts when she is on her period. there are several hadiths about this:

first: "and do everything except intercourse itself." [muslim, abu 'auwaana and aboo daawood]

second: on the authority of 'aa'ishah who said: "when we were on our periods, the prophet used to order us to put on a waist cloth so that the prophet can lie with the one who has her period." one time she said: "... he can then fondle and caress her." [al-bukhaaree, muslims and others].

third: on the authority of one of the wives of the prophet who said: "when the prophet wanted something from one of his wives who was on her period, he put a cloth over her private parts, and then did whatever he wanted." [abo daawood: saheeh]

when she becomes clean of any menstrual blood, and the flow stops completely, it is allowed for them to resume sexual activity after she washes the place where the blood had been, or performs wudhuu', or takes a complete bath. whichever of these three alternatives she does makes it allowed for them to resume sexual activity, based on allaah's statement in the qur'an:

this is the position of ibn hazm, 'ataa, qatadah, al-awzaa'ee and daawud az-zaahiree and of mujaahid: as ibn hazm says: "all three of these are  purification - so whichever of them she uses after the cessation of her periods, then she is lawful for her husband."

the same term is used to mean washing the private parts in the aayah revealed concerning the people of qubaa:

there is nothing here in the aayah however, or in the sunnah, to restrict the aayah in question to any of the three meanings - and to do so requires a further proof.