The phrase "enthusiastic thumbs" is a fun way of describing someone who is very eager or excited about something. It suggests that their thumbs, which we often use to show approval or excitement, are showing a lot of enthusiasm. Full definition
We had this tonight as a treat (other than the whipped cream looking stuff — because we didn't know what it was) and it got enthusiastic thumbs up from husband and son. (elanaspantry.com)
(However, I must note that I do give her two very enthusiastic thumbs up for Insidious as well.) (shockya.com)
Okay, back to Meghan: Despite its purposeful messiness, the bride - to - be's look delivered a laid - back, effortlessly chic vibe, so we give it two very enthusiastic thumbs up. (thezoereport.com)