I will give you a breakdown of how I and my partner were able to solve this problem. To be sincere, I haven't been able to master how to help myself loosen up a little bit down there, so it took a while before I was able to learn not to be such a frustrating tight-ass:
Step 1: Get used to objects going into your asshole.
You can begin by adopting a comfortable position that makes your ass accessible when you are in a laying position. For me, laying on my side works best.
Ask your partner to lube up his fingers if he loves using that, provided he has no open wounds and his fingers are trimmed. Using a small probing toy also works. He should lube up the inserting object and your asshole. Let him massage the opening for a while before inserting his fingers of the toy into your butt hole. He should start by inserting it a bit, bring it out, massage the hole more, insert it again, and bring it out again. This procedure should be repeated a soften as it takes before your partner can easily insert his finger inside you.
The entire procedure involved in massaging your butt hole and inserting either a toy or a finger helps to relax those muscles subconsciously.
Step 2: Take width
It is possible that your partner's penis is much larger than his fingers or even the toy. If this is the case, do the first step with a larger toy or multiple fingers and a larger quantity of lube. Do this slowly, stop when it starts hurting, and check whether it is best to commence within a few days, weeks or months. Your major goal should be to work up to about 3-4 inches in perimeter (2 fingers, 1.5 inch diameter). Once you are able to take that size without feeling any pains, you can then proceed to the third step.
Step 3: A penis or penis-like instrument
Now, you can start playing either with your partner's penis or any other object of that size. But you have to repeat step 1 (massage, then insert, massage again, and insert more). If your boyfriend gets an erection by rubbing your ass with his penis tip, he can use the penis tip to massage gently but slowly. Once he feels any resistance, he must stop and repeat the whole massage-insert procedure. Again, he must use some more lube. He may also slip around a bit as well. Alternatively, you can buy a dildo or a bigger probe to achieve this.
He can equally quite trying to penetrate and get you to push yourself on him, to enable you ascertain the extent to which you can take it. I did this to my boyfriend every few minutes.
Eventually, you can be able to take a little of him, maybe the head only or a little bit more. This was where I stopped. The next time we tried, I relaxed a bit more and went a bit further. We kept doing this until I could take the whole of him in that position. We did a number of penis-in-butt classes before we could get that far.
I'm not sure if the above content is enough for you. If you still have any questions about how to make anal less painful, you can refer to this page: