1. Have 2-3 beers
2. Use your hands and tongue on her first, make her cum once before you take out your cock
3. Use condoms
4. Take small breaks when shit gets too intense - but don't just stand there, eat her out!
5. If you're fucking her and she's really enjoying it and taking a break is out of the question, think of something nasty like your grandmother's feet, your tax reports or separatists.
6. Most of all: BREATHE. I mean relax and breathe by the guts, relax your lower body it helps.
When you figure out how to control it, you'll be the master fucker.