Any suggestions on how to stretch sit on hard plastic slippery train seats? The bottom seat is concave in center. Lots of time spent daily on commuter train. Thank you.
Yes, slippery train seats can be tricky. A nice solution for me and some of my students is to wear a backpack (or you can place your purse behind your back) and go through the motions of Stretchsitting: lengthening your back and hinging back onto your backpack which then usually stays put against the slippery backrest. This way your backpack or your purse can act as a Stretchsit Cushion.
About that concave seat. If you can, place something in the concavity, a folded scarf works well. If you have a long commute, I think it is worth bringing something with you to even out the sagging seat. Just remember to pick it up when you get up.
I hope this helps,