To spit or swallow after oral sex is actually a false choice, since these are not the only two options. In fact
most girls (gay men as well) choose to swallow, or do not allow the man to come in their mouth at all. Very few intentionally take a load in the mouth only to
spit it back out.
Man: So, spit or swallow, baby?
Woman:
Umm... maybe you could come on my boobs instead?
Man: Oh.
Uhh... yeah!
That'd be awesome!