This is a 3D-Printable model of a burdizzo-clamp, that is usually used to castrate animals. It also finds use in the BDSM-World as a toy for a little mindfuck.

This is a point I have to absolutely highlight: THIS IS A TOY! Do not use this device to attempt any real castrations. This is a tool for demonstrations only. Actually using it on someones body can result in serious injury and is heavily discouraged!
Although this clamp does not close as tightly as the real ones, it can still result in injuries, if you use it.

Since I am not a professional designer, this surely can be improved a lot.

To print this, I just used plain, simple PLA. Supports were used for every part, especially the clamps will need them. To assemble the clamp:
1) The Small Axis insert needs to be printed twice and then has to be pushed in the middle axis to connect the two clamps together. Position the clamps first together, then insert the axis inserts, otherwise you can't fit them together later on.
2) The Handles need to be put together by aligning the bearing in the middle.
3) Attach the assembled clamps to the handles by carefully spreading the axis holes from the clamps and put them over the bearings on the handles.
4) The small axis cover needs to be printed 6 Times to cover and hold every small axis.
5) To hold the middle axis in position, print and insert the middle axis cover.