I've been working on DPT with Annie in the house for a few months now. We started the public version in class a few weeks ago. I was feeling miserable and hurting, so I sat on the floor and asked her to crawl on lap and put pressure on. Ok, let's be honest, I lured her on and rewarded heavily. She thought I was a bit nuts for interrupting her normal crate routine, but it helped.
Head down, which I think you already taught helps teach this, as does crawl (I am doing this sitting on the couch/floor/bed with my legs straight), the challenge is working on duration. After we have worked at it for a while, she falls asleep on top of me, but bridging those two so she relaxes sooner without hopping off has been a challenge. She wasn't ready to commit to napping in public yet though, so probably more work on relax on the floor in public is needed before I try and get her to relax on my legs again! Still hard to do in pandemic times.
I have tried the version where the dog just puts its front legs up on a person seated in a chair and discovered Annie has very boney elbows.
