Pregnancy Question!!

Okay so I'm not on BC,and me and my boyfriend use the withdrawal method. Last night while we were having sex he was flexing his penis while it was inside me,but when he did it it actually felt like his cum was going in me! He said he wasn't and he would tell but it honestly felt like that and right after I just felt extremely wet inside! I'm not sure while he flexed some came out for what. We are not trying to prevent pregnancy and we are not trying to get pregnant,if it happens we would be truly blessed but I just want to know your guys opinions on this. Did this happen to you?