Darwin’s bark [spiders](Caerostris darwini) … have a rich sexual repertoire that includes oral sexual contact. The males routinely salivate onto female genitalia before, during, and after copulation.
Janet Fang from Male Spiders Perform Oral Sex On Females [iflscience.com]
Actually, spiders as a whole are the Marques de Sade (is there a female version I should use here?) of the animal world, as the opening sentence of the article makes clear:
The females of many spider species have evolved giant sizes, and they’re known for extreme sexual behaviors – ranging from mate binding and plugging to sexual cannibalism, genital mutilation, and emasculation.
I nominate this for the best science sentence of the year. This is NC17 Discovery Channel shit.
Note the authors name for extra credit.