Bruce O, thanks for the Rusty Warren information; I always wondered where the chorus came from. As for additional insults, "your grandmother swims after troopships" scans better , and "your sister licks batshit from cave walls" brings back fond memories of late-night singing in the sleazy bars of my youth. BTW, my father always told me that there are three kinds of limericks: 1) the kind you tell to clergy. 2) the kind you tell to ladies. 3) limericks.