"Part of me wants to spank her but I also want to eat her ass. I'd love to find a way to do both at the same time."
"Well, you can't really do that. You have to make a choice. You can't mix them up. During one sexual encounter you either have to spank her or eat her ass. Once one of you has cum, you can then switch to the other. You can certainly eat her ass for a bit and play with her pussy until she cums and then spank her, because once a cum has happened you are into Round Two and everything resets itself. But don't mix up ass eating and ass spanking in the same encounter."
"True, and remember that some girls need their asses eaten and some need them spanked. It's different dynamic. If the girl needs you to be worshiping her eat her ass. But, if she's in the mood to be sub, then spank her and don't eat her ass. If you do both you are sending a mixed message."
"Wait, but why can't you do both?"
"Because women like decisive men. If a guy tried to eat my ass and spank me at the same time it would be like if we went out to a nice dinner and he ordered both the chicken and the fish!"
"Exactly" - as several girls and guys all nodded their heads.