sarcasthumb
When a someone inserts the thumbs up emoji into text, such as a facebook message. But you cannot tell if they're being genuine or sarcastic.
wow, potato sure loves to use the sarcasthumb! She did it the other day when I said found my wallet. Yeah can never tell if she's being serious or actually cares lol. What a honkey!
sarcasthumb
When you insert a thumbs up emoji out of context, particularly after a friend expressed excitement about something. The true intentions of the thumbs is unclear as it seems to be disingenuous, but you'll pretend you meant it nicely.
I was excited about seeing a movie at the theater since I haven't gone in six months, and my friend Potato immediately typed a sarcasthumb after. She's a two faced human who likes to show how great she. She constantly brags about going on vacation. But she'll never admit to the sarcasthumb. She doesn't care about good things happening to her friends she only cares about herself.