We've got a very shallow foam mattress on our spare bed - but standard double fitted sheets are twice as deep as they need to be, so they just flap around!
At the moment I've got those elasticated straps and clips on the sheet to try and keep it in place, but they're a pain.
Surely you can buy shallow sheets? I've googled and searched amazon but everything says that a 10 inch pocket sheet will fit "up to" a 15" mattress. So I'm not convinced they'll be any shallower than what I've got.
Failing that, explain to me how to adapt the sheets I've got! I can sew but have no machine, and I struggle to visualise things...