This is a mold for my Simple Butt Plug.
Print two of those. Sand mold surfaces!
Use M5 50mm screws and nuts for clamping mold parts together. They held to keep everything aligned and closed.
Mold outerdimensions: 9,6cm x 6cm x 2,2cm
Hight about 90mm
Diameter about 35mm.
Volume 33.8cm3 -> you need about 34ml of water for an ice toy.