to stef a bowl (of weed) is to basically use it as a microphone and instead of hitting it, you just hold it and talk and talk and talk...
"come on man, quit stefing the bowl and hit it already"
verb. to stef a bowl (of weed) is to hold it in your hand before hitting it for an extended period of time, usually while talking or chatting.
"come on man, stop stefing the bowl and hit it already."