By the way, sliding and gliding are the same thing.
nope.
Gliding:

Sliding:

And as I said, in both you are (at least on one phase) traveling into different direction than your craft's nose points to.
Your thinking is too much bound to background co-ordinates. If you don't give the space craft any relative points to compare its velocity onto, there are actually precisely two types of detectable movement for a space ship:
-rotation, involving angular acceleration and angular velocity
-linear acceleration, ie. changing the velocity vector of the craft.
In your first example, which you call "gliding", the space craft rotates around its CG, but doesn't apply any acceleration to any particular direction, which causes the CG (center of gravity, or mass center) to travel at constant speed.
In your second example, the craft applies lateral thrusters to one side for some time, then applies sme amount of impulse to other side, resulting in a movement of position sideways.
However you look it, both "sliding and "gliding" are simply one exactly same thing: F = ma, and its angular version M = J α (α=angular acceleration, J = angular inertia of object). Sliding and gliding are, as I see them, arbitrary names given to two types of maneuvering, and I don't know whether you made those definitions up yourself or if they are made by someone else, but I don't think it's in any way necessary to use those definitions... You can, of course, call different maneuvres all you like, but all maneuvres still consist of same things - combinations of angular and linear acceleration, and that's all there is to it.
