Someone types a noun and then you write one that starts with the last letter of the that noun.

For instance,

Someone says "Onion,"

and then you say "Nincompoop,"

and some else says "Party!"

the next person would be stuck with a "Y" word.

I'll start...

touch

habit

thAC0 bonus

sunder check

killing spree

experience point

Tomtom

mat

thimble

egret