Clicking during V-ups

Last night I was working on v-ups and I felt a clicking somewhere around my coccyx/tailbone on each rep. It didn't hurt, but felt weird an uncomfortable. Any ideas how to prevent or avoid this?

Hi Nicholas,

If there is no pain associated with the clicking, you shouldn't need to worry. What type of surface are you doing your v-ups on? 

Thanks for the response Jeffrey. I was doing them on rubber stall mats in my garage. 

The rubber mats are ok to use but Id recommend using a little extra padding.

Try making the surface your are doing your v-ups on a little bit softer to see if it helps