Ashiatsu - I will be safely walking on you.
Shiatsu - I'll be on the futon, in a kneeing, sitting, or crouching position, using my hands, elbows, kneed or body to perform Shiatsu.

In short, most people find Ashiatsu far more comfortable than traditional Deep Tissue Massage. Ashiatsu has been coined, "the deep tissues without the pain".

Everyone has a different comfort level. You can choose what works best for you!

After the first session, maybe. Some people get relief from work that creates soreness. I strive to accommodate a wide range of intensity levels.