Firstly, I would ready this as bum play eg finger up the bum for him and her, rimming and anal. All of which are perfectly acceptable (and can be enjoyable) when done safely with consenting adults.
If you think back, there was a time when "most people" considered any sexual position other than missionary to be wrong. There was a time when "most people" considered oral sex to be disgusting.
What happens between my DH and I between the sheets is actually none of your business. Sex is for pleasure and procreation so why deny or condemn a consenting couple something that they enjoy because it's not to your taste?
I'm surprised so many people have a problem with anal considering many of them have a stick up their arse