For some stretchy and vibetastic time, give the Malesation Inflatable Butt Plug with vibration a try.
The main materials used on this item are silicone, tpe and abs and they are guaranteed to be body safe and Phthalate-free. The tapered and ergonomic design slips in easily and then you can start pumping it it for a great stretch and full feeling.
If you need additional sensations, turn on cycle through the 7 levels of vibetastic vibrations and shoot for the moon. Needs a pair of AA batteries. Measures 4.7" long with a deflated diameter of 1.8".