I have a funny story about Nuvaring...actually it's more humilitating.I hated mine and could feel it in my body.Turns out,my boyfriend could feel it too because he got STUCK ON IT!He got the tip of the condom (I hadn't had the ring inserted for very long so we used back-up protection) stuck between the ring and my cervix and it was pinching him.He yelped and tried pulling it out which hurt me,so I screamed.He held my hips still and pulled out.The condom came off,the ring came OUT,he ran to the bathroom to check his penis and I lay in bed panting for all the wrong reasons.
If thats not a strange side effect,I don't know what is.