A play on "Redpilled," Thiccpilled means someone (or something - usually a statement or action) is awakened to the truth that thicc girls are the most attractive.
Girl: "I'm getting too fat, look how big my thighs are getting"
Guy: Fat? I think you mean 'Based and Thiccpilled.' You're looking better than ever.
Guy: Fat? I think you mean 'Based and Thiccpilled.' You're looking better than ever.
by Austrian Snekonomics October 9, 2020