husbands kink

so my husband has always been a bit basic when it comes to sex, and for the past year I've been trying to get him open up sexually, well....come to find out his kink is uh...gaping?? and idk how I feel about that, I mean I'm all for anal, and I like pain in moderation, but this kink of scares me. any tips on how to enjoy it? or get into the right frame of mind as to how to go about it maybe a little more painlessly....