So, yes, a man can tuck his balls into his abdomen. Men's balls develop inside their abdomens before birth, and drop into their nutsacks during infancy. After the balls drop, however, the little cavities in which they developed remain, and most grown men can pop their nuts back in. But popping your nuts back into your abdomen won't rid you of your scrotum, nor does it hide your cock. Unless that guy in the chat room was some sort of freak, I doubt very much that he could get everything nuts, nutsack, cock into his abdomen.
Gaffs are tight undies that smush and conceal men's private parts.
With these slingshots we bring down many a Goliath. In general, I think sex in parks and pig rooms, drugs, and open relationships are unhealthy, and, unfortunately, the norm among most gay men. What I want is a relationship, or even . . . I'm all for gay marriage and adoption. I just want someone who's virtually normal.