The default configuration and setup of the aircraft is designed like this by McDonnell Douglas. There isn't anything specific in my aerodynamics to enable spinning, i.e. I didn't add things to 'make it spin'....
There are many ways to fly into a departure inadvertently however it is all dependent on the configuration, a little bit of misconfiguration helps and a very high AoA (>20 degrees) before trying to make it depart.
With a full load of missiles and fuel it's much harder to get into a spin, and generally the mass distribution of the stores will help to prevent spining.
So configure as per the screenshot. Pull back on the stick and keep it there until it starts to spin.
Important items;
CG % MAC: around 0.04
Gross Weight: around 42,000
Left engine out.
A slightly more realistic example is to set the CG to around 0.11, again with the left engine out, and try to maintain altitude by pulling back, and at around 110kits start to increase power. Then try to keep the aircraft level using just the stick and increasing power to maintain altitude; i.e. make a pilot error of adding thrust without realizing that an engine is out and then make it worse by adding more thrust and keeping the stick pulled back.
Most of the time the pilot is trying to avoid getting into a spin, and when it does happen it's usually because they're trying just a bit to hard to do something else. Trying to recover an approach and land, trying to turn to hard or climb to fast....
also don't forget that the MPCD will give you advice about how to recover. It's not always correct, and the throttles bit doesn't show anything yet, but it is generally better than nothing, and throttles at idle is generally a good idea for recovery anyway.