Get a dildo with a vibrator pocket for a bullet vibe and the Tantus Suction Cup. Both Tantus and Vixen make toys that have a vibe pocket in them, maybe others as well. Don't know if the Suction Cup will work in Vac-U-Lock dildos.
For a dildo look for silicone. Silicone has come down to where there's little reason to look at jelly or any of the other soft materials. Silicone will last for a lifetime and can be cleaned and sanitized easily.
Alternatively some of the Fun Factory dildos have OK suction cups, but they need almost glass-smooth surfaces to stick to.