Bottoming is difficult for me (even as a bottom) because 1) I don't do it a lot, and 2) ADHD can make intimacy difficult.
That being said, there are a few things to do that can make it easier:
1. Get a toy. It doesn't have to be a dildo. It can be a prostate massager or a butt plug (but something small). This will help you get used to having something in there.
2. If you decide the dildo is how you want to go, go to a sex shop (if you can) or look online at places like Mr. S Leather. Go for something in the 5 to 6 inch range and a small diameter. No need to shock your system. Once you feel good about how that feels, then you can go up a size.
3. Douche and go slow. If you are alone, have a glass of wine (or a shot of bourbon) and play with yourself. That hole needs to be relaxed before anything is going to get in there.
If you are with your boyfriend, things change a bit.
1. Douche. Get a bulb douche or an enema kit and follow the instructions. I use tap water, but you can also use distilled.
This is a great guide to how to do it.
2. Don't eat a lot of food or greasy food. It can make things ... unpleasant.
3. Have your guy warm you up. Rimming and finger play can be used to open your hole and should be done until
you comfortable moving onto the next stage.
4. Push out as he's coming in. If he's going for your prostate, push your hole out as if you are taking a shit. You're going to want to tense that fucker up. Don't.
5. GO SLOW! Rome wasn't built in a day and your hole isn't going to open up in seconds. Have him go in and check in. Go a bit at a time, breathe through your nose and out through your mouth and make sure he checks in.
6. Use a lot of lube. Like,
a lot of lube. Lube is your friend. I like water based, but some don't like how quickly it can dry.
7. Listen to your body. When things are going good, you will know. If something seems off, stop the action until you are comfortable.
8. Keep a towel handy because shit happens.
9. Have fun. Sex is one of life's greatest joys and the best sex includes hot and sweaty times, but it also includes fun and laughter.
Hope you guys have a good time and just remember to breathe.