I put Autosoft 90 (and TruSteel occasionally) on my outer thigh (on rotation with a few other sites).
If I'm standing with my arms at my sides, it's about where my wrist hits. Sometimes a bit more toward the front of my thigh.
I also use my upper outer arms and my butt, below my waistband.
When I put infusion sets on my thigh or butt, I find it most comfortable to have the tubing aimed horizontally. I find it doesn't get snagged on clothes so easily that way. I still need to be careful going to the bathroom and changing clothes, but it doesn't get caught as often.
I don't find that any of those sites (thigh, butt ot arms) hurt at all, but everyone is different.