Synonym for hammered or smashed. Meaning to get high and/or drunk to an extended degree and affected by drugs to the extent of losing control of one's faculties or behaviour.
Origin: just made it up when chatting to some gal whom I thought was speshed
Wasn't there some party last night?
Yeah Emily was so speshed at the end
A spedshed is the Special Education classrooms, where the speds go. Its an extension to the insult "sped".
Friend: Yo you hear about the new girl?
You: No? What is it?
Friend: She's in the spedshed! For all her classes! LOL!
You: What's that?
Friend: Sped shed? It's the special ed classes!
Being speshed by somebody is like a girl in your class at school treating you like you are stupid to trick you into thinking they want to be your friend or something