I think it’s pretty the song itself is about a sexual fantasy. Given the era the song was written in, I’d be willing to believe “crimson and clover” is a sexual euphemism. The singer is talking about taking a girl’s virginity, causing her to bleed slighly. As for clover. . . .who nows? Maybe they’re doing “it” in a field, mayber it just rhymes with “over and over,” etc.