1. Noun: The amount of weed you have bought is your portion.
2. Verb: To portion is to divide weed between people.
1. That was an amazing portion, we got 50 joints out of it.
2. Shall we portion out the weed man? I've gotta go in a minute
Sexual intercourse, usually used to describe said act as served to a man by a woman. Made famous by the British comedian 'Jethro'.
I was round the back of the chip shop in Bodmin and the owner's daughter popped out and gave me a portion.