**WARNING:- for shear comical use I'm using this pose, get offended by it at your own risk ^_^

Step 1 –Need to get a pose
For this you ether need to be lucky enough to be given a pose or buy one from someone else or just use BorisTheEngineer's pose tool and make your own (Link). Poses use XAF for the pose and XPF for there face (Face is not required to make a pose work)

Step 2 - Adding your pose to your scene

Ok now you have your pose hears what you do to add the custom pose into the scene. Load up your scene and your normal seating nodes file, position a normal standing or sitting position where you want your new custom position to be. Now in your XSF file change the name of that position, for example it says "seat01.Standing" Change the Standing to a name you want your position to be called, in this case I'm using Test as my position name so that will now read "seating01.Test", save and load it into your previewer. Now in the actions tab click add. Where it says Trigger change it to stance.PoseName replacing PoseName with what you named your pose, in my case its Test, so it will read stance.Test . Put these settings now

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Avatar ID's:  80,191
Stop After: Longer Effect ends
Composition: Replace

Once those are done where it says Skeletal Animation click brows and go load your XAF pose file (and if you have one your XPF face position below) click apply and it should be done, below are the settings I used and the first pose I made
 

-Happy to accept gifts of what you made to NEO1471 if you found this helpful ^_^