@mikehunt42 Please do NOT follow the advice of the lubes that numb the muscles!! The #1 rule is if you feel pain, you stop right away! And you will continue later or another day. With time you will be able to open your hole more and more. But never accept pain. It is not normal to feel pain, pain is a signal from the brain that you might get hurt, so how can you realize you are hurting if you asthetize the area. And believe me injuries in the anal area are very painful. Plus, you're supposed to feel things to enjoy sex, if you're anesthetized, it would be sooooo dull and this is NOT the objective. So never accept pain, even if the top is the sexiest man, tell him to fuck off.

In regard to training your hole. Here are some beginner's tips. It's all a question of mechanics, it's all about anatomy and a bit about psychology.

You have to combine contractions of your hole (push / squeeze), your breath (exhale / inhale) and take the right angle (when lying down the dick faces down to get in. When on all fours the dick faces up).

Push an object (dildo or any other phallic-shaped thing) against your hole without inserting it. While you inhale for 5 seconds, you squeeze your hole, then you exhale for 5 seconds and push your hole at the same time. Do that multiple times and you will feel that your hole will suck the object in, even you will be surprised how magical it is.

On a side note, you have to know how to control the pelvic muscle (the one you squeeze when you want to stop peeing). You have to strengthen this muscle, every day you tighten and you loosen your muscles for several minutes.