Worst fears of anal and need advice/suggestions

My boyfriend of 4 years and i were ya know “doing it” 😂😂 and We talked about introducing butt play. And I’ve literally always been terrified of it but I agree because why the hell not! So he grabs the anal beads and slowly puts them in. Well I’m like ehh this isn’t that bad! Well we finish having sex and he goes to pull them out and it feels stuck. And I start freaking out a little and I just rip it out (bad idea so sore today) but the first two anal beads were covered in shit 🤦🏻‍♀️🤢 I’m mortified at this point! So i get up and run/fast walk ( can’t wake the baby sleeping in the living room) to the bathroom and quickly wash the beads and wash up. I’m mortified about how to go about this again without it happening again! Any suggestions or advice?