WHAT?!? Thatās super cool.
I havenāt played it many times, but it kind of blew my mind when I saw Escher stage cradling Alien Poker a year or two ago at Pinburgh. This is a sweet add-on.
But I guess maybe not that useful since usually youāre putting it up top or into the drops which can be done equally from either flipper?
Are traps like that allowed under the rules?
Yes.
In situations where a ball is trapped in a way that it can be released through player action other than shaking or bumping ā for example, a ball at rest underneath a flipper or any other mechanism which the player controls ā this is not deemed to be a stuck ball. Balls trapped in this fashion during multiball modes are not generally considered to be a rules violation, although the ruling will depend on the exact machine and situation.
Except that leaving a ball in the shooter lane on a manual-plunger machine meets all these requirements, but you canāt leave it there 
I like on games like Dipsy Doodle (or the upper right flipper of Black Knight) to hold the flipper up when the ball is heading towards the thick part of the flipper and going to roll over it, and then drop the flipper right as the ball makes contact, using the spinning flipper to push the ball back into play
Shooting up top is easier from the left. I like to cradle on the lower right, then shatz the left inlane to spot 1-2 kings, then shoot it up the right orbit
This actually works every time on my Sorcerer.
On some Starship Troopers, a trap on the right flipper resting against the mini flipper will send the ball straight into the saucer on the lower left side of the play field by activating the mini flipper. It works ~100% of the time on the one I play.
Thatās actually beautiful. It never wouldāve even occurred to me that it was possible. Itās amazing to see a player shake a ball out from halfway down an outlane. To cradle separate four balls on a flipper and make four distinct shots. But somehow this is equally enjoyable.
Starship troopers has a ton of little tricks you can do with that right flipper configurationā¦the most useful probably being a tiny flipper drop catch to a trap on the standard sized flipper.
The Kirk Post pass can also work on non-Kirk games. It all depends on the position of the post and bounciness of the rubber. Different WOF pins will also let you do the Kirk Pass, for instance.
How āgame specificā do you want to get?
On the Stars in my basement, when the balls (rarely) get trapped on the cupped double or triple bonus inserts, itās a super easy backhand of the pink or yellow Stars! 
Yes, that drop catch is crucial considering how often the game feeds from the scoop. Get Orbit MB going and you can left orbit - dropcatch - left orbit - etc. Another important use is slowing down balls for a trap on the lower flipperā¦ those bumps off a normal flipper that would go SDTM will usually trap perfectly when bumped from the upper flipper to the lower.
Never would have considered staging that flipper to pass it. Funny, I overheard people talking while playing during Pinburgh: āThereād really be no purpose to staging them anywayā.
WRONG.
Hey, it won me two pointsā¦
While not a flipper skill, @gammagoat @PinballProfile and I were playing a game of Grand Lizard over the weekend, and Ian managed to use the Magnasave to pass the ball from the left magnet over to the right magnet, so that was quite fun to watch. I think it might be the new eyewear allowing him to see the magnetic field 
Either that or heās actually Magneto 
Speaking of Magnasaves, I do a move on WCS that I find semi-useful. After the second multiball lock when the scoop becomes lit, I plunge the ball and hold up my right flipper. Usually there isnāt enough juice to get a hop over to the left flipper, but if you use the magnasave you can pretty much ensure that youāll get a ball cradled on the left every time.
I figure that Iāve never actually successfully used the magnet for a legitimate save, so I may as well use it for a guaranteed shot at the scoop from a trap.
Yep. Also if a ball is traveling to fast down the left inlane to trap up, I use it then too.
Also if Iām in MB, and trying to get a cradle separation, it can help pull the ball or balls over to the left if they seem they are about to fall down to the drain from mis-judging a bounce.
Or you can do this! 