Hello, and welcome to the Board and its Forums. I hope you enjoy participating.
Our major reason for being is to help others by providing how-to information, and information. It is important to know that anal play and stimulation should never be painful. Plenty of couples incorporate anal play and prostate massage into their lovemaking, regularly. What your boyfriend did was wrong only in the fact that he did not learn the proper technique beforehand. So, if you have an open mind on this, please read the article linked below and try, again. Both of you can benefit and enjoy the stimulation that comes from the activity.
You will find an Index at the top of the main screen that contains links to many helpful insightful articles, some with how-to information, also. Please browse the Index and read those articles that interest you.
"Playing Ball" and How To Tips for Prostate Massage
This is also an excellent tutorial for people interested in and concerned about the how-to of Anal stimulation as well as play.
I hope this is of help.