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.
by bassjesus June 17, 2014
Get the Jam Seshmug. by JayDoopy April 1, 2019
Get the Jam Seshmug. Subconsciously dancing to a song then noticing that others are doing the same, which only makes the group jam more enthusiastically.
by ahhhsuraah January 20, 2011
Get the Jam Seshmug.