The accumulation of rogue hairs from a woman's head on a man's genitals after sex; similar to the gathering of free floating seaweed. Usually not noticed until the putting on of underwear or taking a shower.
1. "You know Susie is bulimic, right?"
"Well, that would explain all the sexweed."
2. "I can feel some sexweed tangled around my balls."
3. "I didn't realize how hard I was pulling her hair until the next morning when I found tons of sexweed."