What are they?
For the working girl it's pretty obvious that her ass keeps her earning during times of the month when others are limited to their oral skills..... And let's face it.... Some women are so bitch that time of the month that putting your dick in their mouth does not make a lot of sense if she has all her teeth!
Surely though... There are other benefits.....
Here is one for Ladies dealing with Anxiety to consider....
GABA deposits have been found in male semen, these are typical found in anti anxiety drugs. Produced in the human liver they do exist in semen ejaculations. Naturally, following anal intercourse (BB) then this semen will quickly be absorbed into the receiver's bloodstream via blood vessels in the rectum.
So... Although the sight of a massive dick prior to Anal insertion might make a few ladies a bit anxious... Taking a fresh hot load in the ass should make them feel better in the end!