Lowest settings. Short length, low intensity.

You put both the 'length' and 'intensity' dials to their lowest setting, then point the tiny little thing at Ana. Okay, this does seem a little stupid.
"You ready?" You ask Ana.
She holds her arms out to the sides, in a 'come at me' gesture. "Hit me!"

You pull the trigger. The little thing lights up for a second, but nothing else happens. You hold it up to examine it.
"See?" Ana says. "Told you it was bull- hnnn." You look back up at her, your expression of shock reflected and magnified on her face as her sentence is interrupted by a very girly moan.
"W-what the- ah!" Her face is flushed. She puts one hand on her mouth and one hand on her belly. She's staring at you in shock, wide eyed, but then her eyes lose focus as the first shudder arrives. Her hand barely holds in her moans as she leans forward on the window frame, chest heaving and hips gyrating. Her back arches and she grabs the window frame, her eyes closing and her mouth forming a clenched smile-- and then she relaxes as she comes down from the high. She looks satisfied as she rides through the afterglow.

Then she remembers where she is. Her eyes dart open and lock with yours, a radiant blush colouring her features. She quickly stands up and adjusts her clothes, before closing her window and closing the curtains. Well, that's a perfect test if you've ever seen one. This thing actually does have the power to give someone an orgasm just by pulling the trigger. Just what are you going to do now?