Well, Youtube and I just aren't meshing today.

Here's the basic dorsiflexion mob:

Stand like you would for a calf stretch (kind of a lunge, gonna mob the ankle that is back)

Turn the back foot inwards slightly (pigeon-toe)

"Squat" (bend both knees, as far as you go) while keeping both heels on the floor.

This isn't a stretch, so you may feel NOTHING.

Do about 10 times, about every 2 hours. May as well do both ankles, since you sound like both are sticky.

You may notice a difference right away, might not notice anything for a week or so. Stop if it makes you worse afterwards!