1. Suggest she give herself an enema beforehand
2. If she doesn't, make sure she didn't have Chipotle for lunch
3. If her eye balls start to bulge significantly outwards, or if you see the tip of your dick begin to protrude slightly out of either of her nostrils, you've probably gone too deep
4. When you pull out, if she still has an anal death grip on your dick, don't just yank out anyway or she's liable to blow an O-Ring gasket permanently. Permanent 'cauliflower asshole' is not a pretty sight, she'll likely never forgive you, nor will you ever be able to un-see that and it will haunt you in every other sexual encounter the rest of your life.
2. If she doesn't, make sure she didn't have Chipotle for lunch
3. If her eye balls start to bulge significantly outwards, or if you see the tip of your dick begin to protrude slightly out of either of her nostrils, you've probably gone too deep
4. When you pull out, if she still has an anal death grip on your dick, don't just yank out anyway or she's liable to blow an O-Ring gasket permanently. Permanent 'cauliflower asshole' is not a pretty sight, she'll likely never forgive you, nor will you ever be able to un-see that and it will haunt you in every other sexual encounter the rest of your life.