VAC-U-LOCK is a private sub-brand of the American company Doc Johnson, which stands for special reducers and suitable erotic aids that are compatible with each other. This reducer is typically shaped like a cylinder with triple protrusions on the sides – a kind of mandrel that is inserted into a compatible aid (usually a dildo of non-/realistic appearance, or a vibrator) and then can be used for more lubrication.
These tips are quite easily interchangeable so you can rotate multiple toys on 1 mandrel. With these vacuum mandrels (vac in the name means vacuum and lock means lock = vacuum toy lock) dildos can be attached to various strapon harnesses / harnesses, fucking machines, handles, suction cups and other accessories.
