"oh and" is the new "p.s."
When used properly, "oh" corresponds to "post" and "and" corresponds to "script".
One may add a second "oh and" by simply putting a second "oh" in the beginning of the statement to designate another afterthought. It should read as follows "oh oh and", which would correspond to "post post script".
In context it should read like the following example:
hey man go check out my new epic youtube vid!
oh and dont forget to rate it!
oh oh and make sure you tell your friends!!