When a womans vagina draws in are durring sex either because of her position or the withdrawl of her partners member.
Careful babe you always suck wind when we do it like that.
a type of flatulation that can only be released through the tight clenching of the buttock muscles. the colloquial "suck in your butt" applies here.
Okay now suck in your butt! Whoops...sorry. Suck wind.