That completely invisible but annoyingly effective "glue" that always seems to form between two bedfellows who are cuddling "sans-clothing", creating a damp and tacky "skin-to-skin" bond which becomes (often painfully!) apparent only when either snoozer attempts to turn over or otherwise change position; this is especially a problem on warm nights and/or if one or both slumberers is of the "corpulent" variety.

When you eat dirt for the first time and leave your family to build a shack in the woods