When a guy is lying down with an erection which forms a 90 degree angle with his body. The tip of his penis is covered in semen, hence, a White Castle has been formed - def. by Dirty Ghee
"The worst happened last nite dude."
"I'm layin' there all post-coital after beating it and my mom walks in while I'm still laying there all sweaty."
"Oh shit, that's wax."
"It gets worse- I dart my head up and realize I've got the white castle!"
"Oh my god! Wax like paraffin!"
"For real yo- shit was not hot"