Sorry for the late response! I was taking time off for the holidays.
The dildo should be usable from the main menu once you get it. There's no associated event image at the moment but it will cure Red of any lust related negative statuses.
The vibrator on the other hand should be equipped to Reds underwear. It likewise has no real event images yet but it'll boost your LP gained from other events as long as you wear it. Hope that helps!
In the future I hope to add new and edited versions of existing scenes that make use of these items should the player have them, but for now they're purely just functional in terms of mechanics.