...is fun. Try it!
Set up a looper for 100% loop regeneration (feedback). Then link that
100% to go down following the amplitude of your audio input. This link
should only be active in Overdub Mode (also called "stack"). Now every
sound you make will go into the loop and push down older layers a bit
but when you shut up old layers will stay untouched. If you want to
just play over the loop, without adding new layers, go out of Overdub
Greetings from Sweden