"Don't ask any questions" joke

A guy worked in an adult book store. One afternoon his friend walked in.
The guy said, "Dude, thank goodness you showed up!" "I'm starving, and I need you to watch the counter for me for a few minutes, while I run across the street to get some lunch."
The friend looked around the store, then looked back at his friend oddly.
The guy said, "Dude, don't ask any questions, just sell it to em."
The friend said, "Ok". So the guy left.
A customer came in, and went up to the counter. She said, "I want a vibrator. What do you have?"
The friend said, "We got red ones, white ones, black ones, big ones, little ones and medium sized ones."
The lady said, "I'll take a little red one to carry in my bag."
He sold it to her.
Another woman walked in. She approached the counter and said, "I would like a vibrator, what do you have?"
The friend replied, "Red, black or white, large, medium or small.
The woman asked, "Well, what about the red, white and black checkered one up there?"
The friend said, "Well, I'll sell it to ya if you want," so she bought it.
A few minutes later the guy came back from lunch and said, "Thanks Dude, you're a life saver. So did you sell anything?"
The friend said, "Yeah, I sold a little red vibrator and a thermos."