You're never going to be the best player you can be if you don't move it around. I slap and nudge a decent amount but nothing I wouldn't want somebody else doing to my own game. The only death saves I've seen happened without me trying to do them, balls just bounced back in at exactly the right angle off the apron. I have liberal tilt settings and i still sometimes tilt if its going out the side anyway. I don't attempt to slide or bang back. or rage tilt.
To get started try some slap saves- just moving the flipper over a 1/4" to get a ball in the middle but near the flipper. Another easy technique is to push forward to get the ball away the side drains. That may have been why the guy you saw was humping the machine, using pelvic thrusts rather than his hands. On Mystic, where the side lane openings are huge, I nudge almost every time I hit a sling so the ball will sling with more power, higher, away from the side lanes towards the drop targets. If you use this technique it doubles your ball times. If you watch Papa videos and stuff you see all these techniques. Those guys often tap the sides as the balls come around the orbits to make sure they miss the slings and get to the flippers. I guess the tournament games are set to a steep pitch and the balls curl down towards the tops of the slings.
A while back X2 posted a video of a guy working the ball over from one lane divider to the next to get the ball down the lit lane - that was inspiring - would love to see it again.