Spanking

Hot

Can do, and no it's really only illegal in theory, and hardly even so then. You want to know what's actually illegal? BDSM. Yep BDSM is felony assault and where I am people have gone to jail for grievous bodily harm and malicious wounding that they inflicted upon one another in an orgy. Yep, the unrighteous have cause to fear.

Not advocating it, and I don't want to mods to ban me for promoting scandal. But let's just say I've read some really messed up stuff in the case law, so you're hardly going to be named scoundrel of the year for smacking your wife's ass.