>>7697
The dick doesn't come out of the sheath on its own when he's standing on all four legs, he needs to mount something or sit down for the sheath to pull back. If he's standing and you jerk and fondle the sheath for too long he will get an internal erection.
The trick is to get the base of his penis outside of the sheath before the knot forms, otherwise the knot will get trapped inside and stretch his skin and i think for some male dogs this can even hurt a little because they tend to lose interest.
So what you should do is to give him a couple jerks then pull his sheath back until you see the small knot outside, then place your fingers behind the knot, give him some gentle tugs while you use another finger, hand or mouth to gently rub the tip of his penis.
All the male dogs I've been with have loved getting jerked off that way :)