Question 7: Is free intermixing (of men and women) in weddings permissible? What is the ruling on men’s dancing with a Mahram (spouse or permanently unmarriageable relative) and non-Mahram (not a spouse or an unmarriageable relative) women? Moreover, if men are alone, will there be any problem?
Answer: It is permissible in marriage to declare and announce it by using Duff (a tambourine-like instrument without bells) from the part of women. But free intermixing is not permissible if they are non-Mahrams. This is a Munkar (that which is unacceptable or disapproved of by Islaamic law and Muslims of sound intellect) that should be removed... read more here.