To over-estimate your realistic prowess with the opposite sex. Also known as a disparaging alternative to a Peter Pan personality.
1. "Man, did you see that chick I was tuning?"
"Aw, Coops... you're such a Tuckfuck."
2. "GT is in the house, ladies, show me some ass!!"
"Someone has a bad case of Tuckfuck."
to tuck your dick behind your thighs & proceed to humping your thighs until ejaculation. hence:
Joey: man i'm so fucking horny i'm tuckfucking right now.
Bo:oh me too.