My bf & I had protected sex, he finished but I didn’t. As he wiped, I sat on it & rode it for about 10 seconds. He put on another condom & we took off. After, I asked him to buy me a plan b because I didn’t want to risk it & he said he’d rather not because it’d be unnecessary as he didn’t cum in me & it takes a big enough amount to go in in order to impregnate me.

I’m aware that unprotected sex puts you at risk for pregnancy but is the big enough amount part true? CAN I get pregnant this way if I don’t take a plan b?