Simple, Mount-anywhere Headphone Cradle

Uses extremely-sticky 30 millimeter-wide double stick tape that is readily available at stores.

A fast print with draft settings, and easy on material costs. Use extra wall thickness and 40% infill for durability. Print on edge for layer strength, and use elephant's foot compensation, if necessary. Sand and smooth off any burrs. Print several for the local DJ, the boat, the plane, the car, the treadmill, and the office. 

Notice there is a rounded side and some flat sides. The rounded lip is to hold valuable merchandise. Apply the sticky tape to one of the flat sides and mount it under the dash, desk, shelf, or wherever it is convenient.

Commercial license. Manufacture as many as you want with attribution. If you somehow manage to make enough money selling these to quit your job (how?), then I would appreciate a 5% royalty.