Something that is totally at home (a bird's nest). Something that is very well thought out and fits perfectly; reference to Adobe Flash (and OOPs programming in general) movieclips where one top level object contains several others, these objects are said to be nested.

Micro marriging is when your partner manages your personal day-to-day tasks with you much like a Micro Manager at work.

putting toilet paper down on a public toilet seat before you put your bare ass on the seat