The sound made while in the act of masturbation.
Mother: What's that strange spleeching sound coming from?
Son: Dude, she can hear my spleech... gross
n. jizz, sperm, male seminal fluid
adj. the color of semen
v. jizz, cum, ejaculate
v. - he spleeched on her face.
adj. - now she has spleech hair.
n. - there is also spleech all over the carpet.