Coastal sand

...one of the sandy dunes just behind the beach. Your tail brushes away some of the rougher sandgrains before you lie back, sinking into the sand a little as you pump your cocks, little torrents of sand running over your gills.

It's quite relaxing, lying on your back, stroking your dicks to the sounds of crashing waves and seabird calls, but - is there any chance someone might interrupt your little self-pleasure session?