To ejaculate in a condom. Coined after the late Julius Schmid, inventor of the modern condom.
"I really wanted to cum inside her but she made me use protection, so I had to Schmid instead."
When you ask someone to suck your penis. Especially effective in regions where the word is used to describe a submarine sandwich.
"I'll take the $60 relaxation massage, and I'll throw in another $50 if you smoke my hoagie."