The act of, as well as the sound made by hitting someone in the face with a suggestively shaped slab of ham. The word is both an onomatopoeia, and a portmanteau of "slab" and "ham".
The timeperiod immediately following sorority rush, where new and existing sorority members haven't had a dick in their hand for weeks. And need it. Like they need it bad.
Fratstar A: "Man, I haven't seen a chick in weeks. My dick's getting chapped.
Fratstar B: "Total cockcity. But sorority rush ends today. You know what that means!"
Fratstars together: "SLAMBALL SEASON!!!"
A shambam is the product of dating ambiguity. When a man believes he's in a relationship with a woman, but has not yet consummated said relationship by rounding second base, then a shambam may occur. Typically, a shambam will involve a club night, where the man will accompany the woman to a venue believing they will leave together. But the woman, believing herself to be unattached, hooks up with another guy and spends the night with him. For our unlucky bachelor, a shambam has occurred.
Mark hooked up with Iris? But I thought she was with Jordan? I guess it was just a shambam.
You mean she slept with Dan? But she went out with Adam last night. I guess she really shambammed him.
When you and your girlfriend are doing the dirty on your friend’s basement couch and you proceed to throw both your legs up on the back of the couch and then swan dive into your girlfriends anus or preferred orifice.
“Hey Jamie? Did you give your girlfriend the ‘ol Texas Slamhammer on my couch last night?”