Complete 3 "giant sets" of:
Post weights used to comments.
We love the thought of you decompressing your spine after a heavy squatting day. The best way to do this is to hang upside down from your ankles. If you have access to an inversion table, use it. We've seen people using THESE too, but I don't know how they got up there. These are especially recommended by therapists and MDs if you've got spinal disc problems. After a workout like this, it could work wonders for relieving pressure on your spine.
If you don't have access to any of these upside down mechanisms, you might try plain old situps. Especially ones done over a stability ball (as above).
Light stretching can work too. Using slow therapeutic stretches of 1-3 sets of 30-60 seconds per stretch can go far to decompress spinal discs and put everything back into place. Remember "LIGHT." This is not the time to try and increase your flexibility a ton. Just stretch to the point where it becomes mildly uncomfortable. There are big differences between therapeutic stretching and stretching to increase flexibility. Trying to increase flexibility after a ROUGH workout like this can overwork muscles and connective tissues. It can lead to injury.