Plan B effectiveness

This hasn’t happened, but I just want to know incase it does.

I am on the Falmina birth control pill. My boyfriend and I recently have been having regular(ish) unprotected sex because I’ve been on the pill for years and I am comfortable, he always pills out like 10-20 seconds before he actually finishes so I 100% trust him.

In the event that he finishes inside me 100% without pulling out once he realizes, what is the effectiveness of the pill protecting against pregnancy? Would I need to take a plan B as an extra precaution because of the 100% internal orgasm? Thanks!