You think you're mortified now, just wait until she sends you a picture of her vibrator! I'm imagining it will have a Crocodile Dundee overdub "You call that a vibrator? This is a vibrator!"

Accidents happen. Apologize and be more careful.

Don't make a big deal of it. She likely won't mention it if you don't. similar to when she walked in on you flicking the bean in middle school. Some things are natural and while it sounds like they are not discussed openly, they can be. But since it sounds like it isn't discussed openly, keeping it quiet will likely be the best tactic....... Don't draw attention to it.

bro who cares!! yes you’re a beautifully natural sexually active young woman!! own that shit live freely with your sexuality & who you are because she is ******* beautiful ♥️

I'd think that she'd be glad, thinking that at least you're not ******* him but taking care of yourself...