I´m not trying to make us enemies or something but I disagree :-)
I do not do any particular warm up or cool down and have gained 1.5”x1” on my dick.
I lift weights (done that for 15 years) and I am very strong and fit and do not “warm up” or “cool down” just do two light sets before going heavy, works fine for me.
I have also been running/jogging for 20 years and I never warm up/ cool down. Just walk to the track a couple of hundred meters, then jogging for a kilometer or two before running as a mad man uphill.
I use to be a elite martial artist and could split my legs like a russian gymnastic girl. My stretching was done at home for 30 minutes a couple of times a week often without warm up (sometimes after running). Main thing is not to go to full power/force at once with the exercise, no matter what kind of training but alow for a gradual increase in force. But a special warm up/cool down is not necessary, nor even proved IMO.