If you give a Duncan a Methos, he'll ask for some lube.

While you're searching the medicine cabinet, he'll spot your toothbrush and ask to brush his teeth. You'll refuse, because it's your toothbrush. He'll smile, and you're not strong enough to resist a Duncan smile, so you'll give him your toothbrush.

After he brushes his teeth, he'll need to comb his hair. Combing his hair will make him want to check how his clothes look, and you'll have to take him to a full-length mirror. Admiring himself will give him an erection, and having an erection will remind him of Methos, and he'll ask again about the lube.

You'll go into the bedroom, and start to search the stand next to your bed. Duncan'll decide to help by looking through the dresser. He'll find your favorite camisole and want to put it on Methos. You'll refuse, because the old guy's shoulders are broader than they look. Duncan will ask to see the Victoria's Secret catalog so he can order something in Methos' size.

Looking through the catalog will remind him of Amanda and he'll ask to borrow the phone.

You give him the phone, but she isn't home. However, the sound of her voice on the answering machine will remind him to check his credit cards.

Checking his credit cards will remind him of the time Methos tried to trick him into paying his bar tab. Thinking about the old guy's bar tab will remind him of beer, and he'll ask you for one.

You'll give him a beer. Drinking it will make him think of Methos' mouth and cylindrical objects. He'll start to squirm in his seat.

Watching Duncan squirm will cause you to excuse yourself and return to your bedroom.

Duncan will follow you. Seeing your vibrator, he'll ask if he can borrow it. He'll ask for some extra batteries, just in case, and when you give him the batteries he'll realize he needs some lube.

You'll reluctantly hand over your last bottle of Probe.

And of course, once he has lube, he'll need a Methos to go with it.