A "Cactus Patch" describes the regrowth of pubic hair on the male or female genitalia. Generally speaking, the "Cactus Patch" occurs one to three days after pubic hair is shaved with a razor.
Encountering a "Cactus Patch" during sexual intercourse can make for a very unpleasant and irritating sexual experience.
"Dude, I got with Stephanie last night and now my junk is all irritated. She was sporting the cactus patch