Jitter Butt
This option adds a small motor to the doll's buttocks area (at the top of the buttocks). When switched on, the doll's buttocks vibrate continuously.
Inside the doll there's a motor with a battery. Control is via a panel fitted inside the doll. It doesn't need mains power to run. One charge cycle lasts for around 30 minutes of use.
Like any electronics in the doll, Jitter Butt is sensitive to moisture. So wash your doll very carefully, avoiding moisture getting into the charging port.
What this gives you
By design, this is meant to increase the doll's realism. In practice, though, it simply adds vibration to the doll's buttocks area. The effect is fairly small.
Is it worth buying
If vibrating stimulation matters to you, this upgrade could suit you. It essentially replicates the properties of a vibrating sex toy. If you like that, feel free to add it to your order.
Only suitable for TPE dolls. Not compatible with the heating system, or with other electronic upgrades.