I’ll echo the same: lube and toys. Ideally use the toys yourself before you and your partner ever go for anal. Talk about anal first then take about a week or two to prepare yourself using toys, eventually getting your hole used to larger sized things inside of it.
It’s best if you can match your toys to near the size of your partner’s penis, so if he’s like 8x6, get a 7x5.5 dildo. You don’t want your toy to be the exact same size that way when he does enter, the stretch will still be a hot new experience and a pleasurable surprise sensation. I tried topping a guy who had never had a dick my size inside him before, but we just could not get me to fit. So he got himself a 7x6 dildo to practice with, which is still under the size dimensions of my stallion. When we met up again, we did a side by side comparison of my cock with his dildo haha, I was much longer than it and a decent bit thicker. Girth is really what you use the dildo to practice adjusting your ass for, not so much length.
The practice the guy did really paid off, it was still a very tight fit for my cock, but I was able to slide in without much difficulty except just going slow so he could get used to my size opening him up wider and wider and deeper and deeper the further I slid in. After I was fully sheathed deep in him, and did some slow thrusts for a bit, then I could do a more normal speed for thrusting and he was howling from how much pleasure he was getting from me plowing his ass.
The most difficult part in anal is usually breaching the rings of the anus as they are tight and only open with proper stimulation, coaxing, and practice. There’s the first ring which you can control to some extent and that’s the entrance to your hole itself. Best way to deal with it is practice opening yourself with a toy and practice trying to relax your hole, if you are tense at all then it’ll make you clench up and yeah anal is almost impossible then. But there is a second ring further in. You can’t control that ring, so it’s the one you need the toy most for so you can get that ring used to being stimulated and opened up. However, only a decent sized cock will be able to reach and press beyond the second ring. A guy my size definitely pokes through and beyond that ring and that’s the ring that needs lots of stimulation and coaxing to slide past. If your partner is less than 6.5 to 7 inches though, I wouldn’t worry about ring #2 as he might not be able to reach it.