Similar to a spotter in weight-lifting, a sputter is an individual whose job it is to monitor someone performing auto-erotic asphyxiation so that the act does not proceed to death.
If Michael Hutchens would've had a sputter, INXS could've been bigger than U2.
A fart with some anal contents (juicy, chunks...) that gets sprayed on your underware.
Dude 1: So there I was in line at the grocery store when I had to fart.
Dude 2: Ya?
Dude 1: Well, my fart was more than a fart...I got some sputter butter...my underware was so messed-up.
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.