is the act of inserting one's penis into the "kneeslit" of another person's leg, and going in and out. The kneeslit is a slit between the thigh and the calf, which is formed when the knee is bent all the way, forming a makeshift vagina. Also known as kneesex.
"did u have sex with her last night?"
"no, cuz she was having her period. but i did kneebang her tho"