So i have been bottoming for the first time and made some progress (practicing with a dildo(, but definitely am having two issues. i can relax enough to take my bf's dick past the two sphincters, but when he thrusts deep, i get this deep raw pain, as if his cock is hitting my bowel wall. this is true in both missionary and doggie style positions. we use plenty of lube, and this morning i woke up with "papercut pain" around my hole. he takes a long time to cum, so fucking lasts for a while. advice and suggestions.
Try laying side by side with him behind you. Best position for beginers. It's not the sexiest position though so it may take even longer for him to cum. I would go for a long regular sex session and switch to anal. More lube.