One man said a caterpillar "pruned" his seedlings when they were tiny. They all lived, and grew branches.
In my experience, an Adenium that wants to be tall will simply grow one stem until it's as tall as it wants to be.
I am careful of the sap, but I don't wear gloves. I do wash my hands soon after handling these plants. I've goofed and tasted the sap, PHEW!!! Bitter as stink! I wipe any blade immediately, as something in the sap will discolor and and make steel blades dull.
Go ahead and chop some, see what happens!