What method do you find works best for forging tenons?

Any good tips?

In general, I butcher (side set) the shoulders, forge the tenon close on the power hammer and finish in swages.

A smithing magician or something similar works great for tennons

When I made a bunch of tenons for a gate, I used a spring swage and then a monkey tool to upset and sharpen the shoulders.

For uniform fabrication, I've heard core drills recommended in a drill press or lathe. However, looking in catalogs for bits, they don't seem to specify the core sizes but they look small. Using large bits may be required. If they are drilled so the shoulder spacing is a bit long, a monkey tool (block of steel with a hole in it, never heard it called anything else) can still be used to upset them.

I've got a monkey tool 'brick' (many different diameter holes all in the same 2x6x1.5 block) for squaring up tenon shoulders and upsetting the area around them

I recently did 20 tenons using my flypress with a stop block, quick easy quiet, Did a final monkey tool run to clean up the shoulders---made the tool from a heavy duty deep wall socket ground down slightly so the end is nice and sharp---fleamarket cheapie.