Just ask yourself "What would happen if I do this?" Then find out All kinds of things can be used for impact play, squeezing, clamping, pinching. Balls can be squashed flat on a table top. (clear plastic cutting board works best so you can see them spread. Any number of things can be used to tie, bind, hang wieghts from. Want weights to hang from your balls? Different sizes of bottles of water. A pint weighs a pound, a quart, two.
Kick in the balls.... swing an object away from you and let it swing upward into your balls as it comes back. I hang different bottles from rafters in my garage on paracord.
Tools such as clamps, vises and vise grips can be used for all sorts of play. Just look around and use your imagination as to what different things would feel like. A brush has two sides... a hard flat one and bristles. All sorts of kitchen implements can used as paddles. Rubber mallets are all kinds of fun. A softball in a long tube sock, rubber bands, chop sticks, even pencils. Skirt hangers can be used as nipple clamps and even hang weights from. Wooden (or even plastic) suit hangers with a bar that clamps the pants makes a poor man's humbler. (use a twist tie to keep it closed)
The list is endless. Have fun.