TN: The word Marisa stutters out for "take it" is "uke." She's trying to say "ukeru" but can't quite finish her sentence. "Ukeru" means "accept my gift", or "catch", but "uke" means "submissive partner in a homosexual relationship". Reimu misunderstands and thinks she meant the latter. Which, honestly, isn't that far off the mark anyway.
It's a double-entendre that doesn't quite work in English.