also used, when a person has no idea at all, what to say next. Whether this is because of a very intelligent insult (ie. they just got pwned) or because it was something totally baffling.
"LOL U NO ACT BLACK"
"well, people tend to not act their race. Take you for example. Aren't you, according to your culture, supposed to be...smart?"
"uh...well....UR MOM IS SUPPOSED TO BE SMART"
"so lyk then I said for him to get out from under the table lol1!1111!!!"
"your mom was under my 'table' last night if you know what I mean..."