Its very simple. you "@ one of my ocs" and I'll make a drawing replying to it.
Example:
@Chill
*Question*
~~~
Here's some OCs I have art of:
Alien (WoF)
Chill (I can't decide on a hairstyle)
Saptar
Aurora
Sandy
~~~
OCs I don't have art of (on TH)
Robinstar (Warrior cats)
Sepiaspot (warrior cats)
~~~
uHHh now go and ask my OCs questions