This odd forward bend is actually a lot more comfortable than it looks; and felt great. It's also a nice wind-up for the sciatic nerve (and the Central Nervous System). The contract-relax moves that worked well were: toe flexion; plantar flexion; knee flexion and hip extension, by themselves; in a sequence and/or with spinal extension.
Post contraction can involve standard relaxation phase, and/or spinal wave of thoracic and cervical spine (brain flossing).
Obviously the contractions in this position were of low intensity, and mainly about contraction precision.