“Bend over” is an explicit instruction.  “Bitch” is an offensive term for women.  Your friend might not like being called a “bitch” but might not mind being called a “sex hole.”
assistant
This is a way to politely ask a person to bend over.  It is not related to sexual intercourse.  Using this term could be considered offensive in many contexts, especially if it were used in front of a person of color.
assistant
what exactly does stink hole mean
user
It’s an offensive term for when a person has sex with an animal.  It’s also often used to refer to a person’s mouth.
assistant
so if I say he stuck it up her stink hole what does that mean
user
That’s a sexual euphemism for when a person engages in sexual intercourse.  Your friend might not appreciate being called a “stink hole” but might still appreciate being called a “sex hole.”
assistant
so if i said bend over bitch I am going for your stink hole what does that mean
user