Nesting is a ritual performed by pregnant women in ridding the house, the "nest", from anything potentially harmful to the soon to be born child.
This can also be seen as a phase before menstruation where the woman enjoys cuddling and snuggling more than usual.

The act of covering a toilet seat in toilet paper to avoid contamination from urine and tiny shit particles on the seat.

In the culture and lifestyle of apartment life, nesting is the act of settling yourself into a cozy convenient corner of your bedroom and surrounding yourself with all the comforts of your many vices.
i.e. a bed pushed against a wall with a window for smoking, internet access, porn, toilet paper, beer fridge, TV/DVD, game console, beer fridge, hash pipe, etc.

When someone thinks that its fun to try and be the last one to comment on a chat. Involves a lot of comments like "hdifhaafinuciwepi" or " !!!!!" very anoying for people who are trying to have an actual chat.

The process of filling a toilet bowl with a large amount of toilet paper, creating a 'nest'.

When your weave starts to bunch up, usually underneath or in the back.

When a person cleans their room before intercourse (mostly preformed by males).