Why do my walls have spasms?

So I was recently playing with my new toys, and I've never fully achieved an orgasm. While use my toy, I have a viberator on my clit. As soon as I hit a certain spot, my body tenses and the muscles in my vagina contracts like trying to push the toy out? Does anyone know what this is? 

Glow Resources

Let’s Glow

Glow is here for you on your path to pregnancy

Glow helps you navigate your fertility journey with smart tools, personalized insights, and guidance from medical experts who understand what matters most.

25+ million

Users

4.8 stars

200k+ app ratings

20+

Medical advisors