Lightly jogging/marching in place for a few minutes may be enough to warm the body to go into a stretch, but you still want to consider including a stretch at the end as well.
Post workout stretches for me feel more productive of the two and are the gateway to relaxing. More importantly, I think you should do what feels best to you, even if it changes day to day.
after a workout to help cool down so you don’t go from exercising to completely stopping your body from moving which also is not good. Also try and go for a quick walk as a cool down when you’re done. 🙂