aka Now You’re Actually Going to Have Anal
You thought about it, you prepared for it (but you didn’t douche, right?!), and now it’s actually time. It’s actually time to put something (a penis, a toy, whatever) into your butt. Obviously you want to make sure this goes well, that it is actually pleasurable for both parties, and that no one is hurt.
The outer anal sphincter (the one you can control) is in a constant state of contraction, designed to keep the anal canal closed. That means that you need to be extremely relaxed and comfortable for those muscles to release. How do you relax? FOREPLAY. Kissing, stroking, petting, whatever gets you to your happy place. This is not a quick operation. Unless you’re relaxed, those muscles are going to want to stay nice and tight.
Your anus isn’t like your vagina: it isn’t designed to stretch and lubricate when you’re aroused. The specialized tissue that lines the anus and anal canal has no hairs, sweat glands, or oil glands, and it contains a larger number of sensory nerves than skin. So without lots of lube to make the area very wet, that tissue is very easily torn (and that will hurt much more than cutting your skin).
If you need more lube, more foreplay, or need to slow things down, SAY SO. This obviously applies to any kind of sexual interaction, but because this may be unfamiliar territory for one or both partners, and because the risk of injury is greater, communication is even more key here. Definitely discuss boundaries before hand. Maybe you even want a safe word!
Don’t Do it Doggy
When most people think of anal sex, they think of getting down on their hands and knees and thrusting their ass to the sky. Sure, that can work. But for the first time, that’s very overwhelming. You’re putting yourself in a very vulnerable position, which may make you nervous. And remember, nervous = tight anus = pain. Try a position where you have equal control of the depth and speed of penetration: spooning, or good ole missionary with your hips lifted (by a pillow, for example.)
Vaginal flora is very particular (which is why we don’t douche, remember?). Introducing things from the anal canal to the vagina is likely to lead to infections. Bacteria that is perfectly healthy in the anal canal is not meant to be in the vagina. So once you’ve put something in your butt (toy, penis, fingers, whatever), avoid putting it in your vagina.
Have fun. If you’re not having fun, or it hurts, or you decide you are uncomfortable halfway through, stop. This should be a pleasurable and exciting experience for both parties. If it isn’t, don’t do it.