If you go to Urban Dictionary and look up "marital aid", it gives you this definition:
1) Truly an item or object used to create a better sexual experience for lovers. A vibrator or sex toy. A dildo or the like. Sexual lubricants. Flavored sexual lubricants. Ribbed condom or the like.
And then you get this example:
Kirk: "Spock, come to my ready room, and bring our favorite marital aid!"
The OED it's not! Slashers are *everywhere*.