Jam Sesh
When at least semi-experienced musicians get together and pull songs out of their ass, working all together non-verbally. Almost always involves hilarious bullshit lyrics.
Good jam sesh last night man, way to pull that riff out of your ass
Jam Sesh
A slang term used by douchebags to describe a jam session. Typically used by shitty/non musicians.
Hey man, wanna get together tonight and have a wicked jam sesh?
Jam Sesh
Subconsciously dancing to a song then noticing that others are doing the same, which only makes the group jam more enthusiastically.
The Black Eyed Peas can usually entise a jam sesh.