[ratimadan]

We do not see anything wrong about swinging with cousins and their wives so long as you enjoy swapping partners, playing and having sexual intercourse between the men and women who is not the wife. The one precaution, as has already been pointed out, is to make sure the women are on pills, and men use condoms during intercourse, unless they (men) are safe (vascetomized) to prevent pregenancy. But, this is the general rule when you swap mates with any couple (cousins or not) and intend to fuck each other's mate.