Anal Ejaculation??? 😂💦🍑

Me and my BF have been seeking new ways to spice up our sex life. He suggested that he cum inside of my anus instead of pulling out like he normally does. I have heard that the sensation can be very erotic, but my main concern is if it could get me pregnant. If I go to clean it up right away, is there still a chance that I could get pregnant? (If even a tiny bit dropped out and onto the outside of my vagina? )