Can you get pregnant if he pulls out but don’t wipe all the cum off himself?

Just curious but if you try the pull out method can you still get pregnant if he pulls out but don’t wipe all the cum off himself then sticks it back in for another round?

Can you also get pregnant if you finish him off first then stick it in second after?

Please explain because I though sperm dies immediately once it’s ejected outside the vagina walls. Just trying to get a better understanding of it before decided this as a form of birth control right for me.