Re: best way to take it in
I've never had anal sex because I'm straight, but I have done anal masturbation many times.
The anus is a bunch of muscles basically. These muscles need to be stretched and relaxes to accept large objects. Obviously, use LOTS of lube. Just when you think you used enough, use more. If you don't have enough lube, it will be painful.
Also, try gradually expanding the anus before your bf inserts his penis by inserting increasingly larger objects. Start with a finger, and keep it inside for a while, allowing the anus to expand. Then insert something a little thicker, and leave it there for a few minutes. Do this until you can insert something about the size of your bf's penis without pain. Then you're ready to have anal sex with your bf.
So a little 'prep work' before you have sex should help a lot.