It makes sense from a why standpoint. I can’t help but wonder about the how.
How did we evolve reproductive organs that are not only sensitive, but also release reproductive cells at climax?
I’m ok with a “we have no idea” answer, but if there is an answer I also want to know.


As in nobody’s looked, nobody can tell, or there’s demonstrably an absence?
Animal reproduction is exhaustively researched.
Some parts of it. If you want to know about bird mating dances, you’re set. If you want to know something more specific, or about an unpopular taxon, you might not be. You said “very few animals”, implying this would be true for nearly everything that’s not a human.
Without more information, it seems like the kind of data that would be available for a couple lab workhorse species if anything at all, since it’s brain- and subjective experience-related.