Tffffff

Tffff is a quick reply method to agree with someone, to let someone know that you understand what they're talking about, or to finish their thought.

It's similar to "I know what you're saying".

Sentence: "I'm freakin starvin'".
Reply: "Tfff" (could mean, I'm hungry too, or I know because you haven't had a thing to eat all day)

Performed by lifting the upper lip and sucking your bottom lip through your front two teeth.