Not to sidetrack the conversation, but where would you sammich in place of an alteration?
Anywhere the alteration starts where the follower would end up after a forward or backwards (non-milonguero) ocho (usually one with the follower pointing more or less in the LOD).
Instead of stepping backwards to the front of the follower and leading an alteration to make the follower move that way, you can also sandwich that follower's front foot and immediately get out of the sandwich, and after the invite to step over (or not step over if you remove that foot fast enough, it's up to the leader) puts you in the same position as after the alteration. Of course, from there you still have to turn 180° to return to the line of dance (or if you weren't in the LOD to begin with, e.g. lead an ocho cortado).
Of course there are still other ways to get out of the sandwich gracefully (including reversing direction yet again, and leading a molinete, from which you can exit in pretty much any direction).
Endless possibilities, but I find I can just splice an alteration and replace it with a sandwich with minimal adjustment at the start, and end up pretty much in the sam position and orientation.
For it to work well, it has to be
small, organic and fast: the leaders steps (usually in a fast rhythm) so that the foot sandwich coincides with a strong beat and puts the follower firmly on the back foot (so that he can invade that space and still maintain the embrace), and the leader's weight change on the back foot coincides with the follower stepping forward again (again so that you can maintain the embrace, unless e.g. the leader wants to then step on his front foot again, lead a microcolgada and turn, which by definition slightly changes the embrace, etc.)
Problem #1 for most people is that they make a sandwich into something "dramatic", which usually means it's too large to stay connected. If it's good, it's barely noticeable and usually small.
It's rather hard for me to describe all the possibilities; the positions are in my muscle memory so I usually move according to my gut feeling and navigational imperatives.