A reference to sex. or the act of sex. Or, you could just be talking about eating pound cake. =]
"So what did you do last night?"
"I went out with Teddy."
"Oh really? What did you do?"
"Well, I pounded her cake and she pounded mine."
"You guys had sex?!"
"Yeah, we were pound cakin'."
when a man/woman cupcakes a person of the opposite sex who is over weight.
Yo, check out Ronald, he Pound Cakin' that big girl. Big Girls need to be Cup Caked too.