Good to know. I had an opponent do this to me. He pushed his pawn up, trying to take one of my pawns. I touched my pawn, then realised if I cut him with my pawn, it would put me in check. But then he said "you have to take it with the bishop". I thought I couldn't play any other move, I had to take his pawn with my bishop, since I was intending to cut his pawn. Then he took my bishop with another piece. I resigned because I was a whole piece down.
meh, I was already losing that game though.
one touch rule

Then you're allowed to make any other legal move!