"To throw-up on one's self"

[Brad Vest]

Alright, I was recently involved in the discussion on stealing first base and
was in the midst of reading a golf book (Bud, Sweat, and Tears) and came
across a line that I would love to know the history of.  I've heard it said
before and it almost always refers to someone choking under the pressure but
the line is:
"You are doing well coming into the last couple holes, don't throw up on
yourself."
Kind of curious where this saying came from, to "throw up on one's self".

Thanks,
Brad