I've got two! Neither are probably funny to anyone else, but they were hilarious to me at the time.
First one, pt: "What's that in your ear?"
Me: "my stethoscope?..."
Pt: "no there's a shiny thing, like an earring"
Me: "oh my daith piercing?"
Pt: "that's a what!? How did they get in there?"
Me: "well it's not that complicated when you go to a professional to get them to do stuff for you. It's a piercing that helps with migrantes."
Pt: "NO WAY! Maybe I should tell my daughter so she can stop using drugs. She gets migraines from working with kids."
Second, while I'm drawing blood after I realized it was my pt's birthday the day prior(.
Me: "sorry I missed your birthday, maybe we can count this as your birthday present?"
Pt looking at where I'm drawing her blood and sees that she's starting to bruise: "maybe you shouldn't give me any more birthday presents."
Lol. I hate hurting my patients to draw blood and the lady was really sweet, but she had horrible veins and it blew while she was fidgeting during our conversation.