Most (possibly all) high-end silicone sex doll have an internal metal skeleton. Hinged at the joint and surrounded by foam, pour the silicone skin on top. Screw the ring bolt into the frame somewhere in the neck or head (depending on the manufacturer). From there you can pause the doll. Wigs usually hide connections. Some brands use this method, while others use completely different suspension systems. Some people have no ability to hang at all. Others ask you to remove the sex doll's head to hang. Unless you can tell us what kind of sex doll you bought, we can only speculate.