It wasn't deliberate. The sand constantly changes. The sand I was originally driving on was damp a couple of inches down. Where I got stuck was completely dry blow sand. I was trying to make my way across a small saddle in 2wd, but when I got to the top, the Jeep lost momentum and started digging in. I backed down, then up the other side we came down, dropped it in 4wd and gunned it. Made it a little bit further, but not quite far enough. On the last attempt, I went left to try to go out at a lower point. However, it was dry blow sand and we sank in up to the frame.
The tire pressure was 15 psi and now that you mention it, I should have aired down further.
Next time!