Two things worth noting

If someone of the female persuasion asks you to wash her back that aforementioned back does not terminate at the midline between her breasts. For that matter it does not extend to her back door. At least not the internal parts of it. And it does not need to be soaped, repeatedly, until it starts to sting.

Actually, while we are on that topic...

Cum is not the best way to flush out the soap.

Oh and the feeble excuse of I'm just being thorough doesn't cut it at all

Sighs OK that might have been a bit more than two things, but honestly the cost of a back wash around here is unbelievably high L