Since I don't have to give up my grammar...

Naw your just sweet on Lews.
Despite the quaintness of all things "Naw", it should still be held accountable to the rules and followed up with a comma. Another item to mention- the word in bold should be spelled in it's contraction form- "you're".
You should know he's easy tessa, so you don't have to give up your grammar for him.
There should be a comma after "easy". (And I do know that about Lews, by the way. It's what makes him so loveable. Besides, takes one easy to know one.)

But he appreciates it anyway
This sentence is missing the ending punctuation. Additionally, it's not the best idea to begin a sentence with the word 'but'. You can do much with 'but', however it's not the best thing with which to lead. And I would know.

Yours
Mad
If you are following the American English guidelines, then there should be some type of punctuation after "Yours", preferably a comma. If you are following the British version of the English language, then no marks are certainly acceptable. Me? I prefer the marks myself.

Well, what about that. It really is better to give than to receive.