Butt Fun

Okay so me and my bf have been together 3 years and were high school sweethearts. As a couple we are super sexual and can't keep our hands off eachother. Our sex life has only grown since we met and we get extremely freaky (lol). We've done anal plenty of times but he has never came while hitting it back there because I'd never let him. Today I was still on my period and even after 2 bowjobs he wasn't satisfied. And I was so horny that when he pulls down the bum of my pants I let him go for it. Several minutes later he came in my bum😨 Talk about a shock. I'm a little sore but feeling pretty normal. Any dangers I should know about when I get that stuff in hole #2? Didn't use lube btw