Pap, according to Merriam-Webster:
1 chiefly dialect : nipple, teat
2 something shaped like a nipple
And according to the Expat-Bob dictionary:
1 a strange soft drink in Chile, lightly carbonated, scented like bubblegum and flavored like a mixture of dentists’ office fluoride treatment and the rubber mold compound they use to take molds of your teeth. Or we could just call it “dentist office flavor.”