For sore bums
 

Seat post test

Best soft-riding rigid seatposts for road, dirt, and gravel - BikeRadar

I was about to post this also. They even mention that the Specialized CG-R (formerly Cobble Gobbler) might be ideal for tandem stokers! It's rare that this usage is mentioned in the mainstream cycling press. My wife is certainly happy with it on our tandem.

I've used the Ritchey, Specialized, and Thomson models mentioned in the article on a single bike, and my subjective favorite is certainly the Ritchey.

I was very surprised by the results as my wife is very happy with the CG-R.

I think the difference is that the other seat posts are designed to deflect to absorb shock while he CG-R s designed to compress.