To move with considerable speed. (From my stepbrother Garrett, who most likely does come from Salinas, CA. So does the word.) Example: A. You should have seen us. We were jamming ass the whole way here. B. If you visit Paramount's Great America in Santa Clara, be sure to ask all the ride operators, Does this ride jam ass? Especially the ones on foreign exchange from other countries.
JAM ASS
Meaning of JAM ASS in English
Slang English vocab. Английский сленговый словарь. 2012