I wrote I'd rather tear except for 2 scenarios:
1) if I am tearing forward into the uretha
2) if a balloon type tear starts in the perineum and explodes out. I hadnt heard of this, but my midwife mentioned it.

Otherwise, I wouldn't want an epi. I'd rather be supported to borth in a way to minimise the risk of tearing (as much as that can be done).

If you want to read more about it - try Henci Goer's the Thinking woman's guide to a better birth.