It's good to warm down when you are finished playing. Pedal tones are excellent for this because they increase the blood flow in the lip area and relax facial muscles. Sometimes it's preferred to use the same fingering in pedal tones as an octave above but regarding to face relaxation it has no difference. If it feels difficult, you can use whatever fingering you want at first. After practising, you also can buzz your lips in a flapping manner to regain circulation of blood. Play these exercises without tonguing.
You can play the last note long as in sound example.
Sound example: Pedal tone exercise 1, Tempo=60
Pedal tone exercise 1
created by jjs