Unprotected sex & the pill

So I've been on the pill for over a year now (since July 2014) and I've been wanting to try unprotected sex with my boyfriend. Sometimes I let him put it in bare but after a few pumps I get scared and make him pull out. Then I'm just anxious all month until I get my period. So my question is, when is the best time to have unprotected sex during your cycle to ensure no pregnancy?