Yeah, it can take a while to fully understand.
Just about everyone learns a mildly paced kicker first, since tossing it sort of back and above the head gives you the right swingpath, but the drive "up" with the legs is most intuitive when you're fully vertical. Gives a ton of spin, but not all that much pace.
Being informed that you need to toss further into the court to generate pace screws EVERYONE up at first, because it's hard to square that with the swingpath you learned previously. The trick is keeping the swingpath exactly the same, but changing what "vertical" means. You have to reorient your whole body in a way that feels unintuitive and, frankly, dangerous. So much so that if you don't put your foot out and land on it, you'll fall on your face. But that's exactly what you need to do. There's still a straight line from the feet, up through the head, and out to the ball. You're just now launching yourself out into the court at a ludicrous angle.
Failure -- or even inability -- to execute this fairly advanced athletic maneuver is why most rec players end up with kickers that move okay, but lack pace and become sitters for opponents with decent backhands.
Yes! No one ever told me, it was over the last week or two, out of sheer desperation and trying everything to improve my service game, that I had a lightbulb moment when thinking, that the forward toss was the key, more forward than I think I should go. Far right and forward.
Instant, my serve improved in quickness, is now about 110-115mph flat serve, pretty consistent so long as I leg drive well off toes, makes lots of snap.
But the kicker disappeared.
Upon thinking, it clicked that this new angle of attack brings the line of my body at a wrong angle from before, which is why it now goes net, net, net, net.
I can't hit it the old way, because mostly, to my mind that is staying in a place of non developing, and second, my kicker was deadly to weaker players I could see that, height and movement too much don't need any pace, but against my coach and high level players, they could smother it, get it with their backhand, or even jump and take it fast for a easy winner with their backhand.
I'm going out today to do a few hours at cones working on ad wide kicker and deuce tee kicker, but with my marker 1ft inside baseline.
A better deuce 2nd serve now I like is a semi-rapid slice or covered serve that it is a bit harder to see or judge the slice when it is incoming, from the pace, but after the bounce once they are already set, the curve continues and throws them off, works very good when they judge it is to their backhand hitting zone, but then keeps curving into their body and jams them up for a bad contact, if you follow that up you can get a volley or shortball kil.