[Sketch] Bondage Tube (Pixiv Fanbox)

In celebration of the new Pokemon game and the adorable Tuber trainer boy, here's a concept inspired by a dildo tube I saw a few other artists do ^^

The tube starts out deflated and the wrists/ankles are put through the straps. As the tube is inflated, the the straps tighten and the dildo inflates. Then you just have to set him on a nice wave pool and the dildo will do the thrusting automatically~