How to explain a Pap smear to my boyfriend

How do I explain what a Pap smear is and why I need to get it done? My bf doesn’t like when I have to get it done, and doesn’t understand why I have to get it done. I’ve tried explaining it but I guess I’m just not wording it right. I don’t know lol.

Update: the reason he doesn’t like it is because the first time I had it done, he went with me and was in the room because we had just found out I was pregnant. It was a male doctor so I was uncomfortable in the first place, which I was making a big deal out of before it had gotten done.