Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
pōtātĭo, ōnis, f. [poto], a drinking, toping, a drinking-bout, potation (class.): prandium aut potatio, Plaut. Bacch. 1, 1, 46: quosdam hesternā ex potatione oscitantes, Cic. Fragm. ap. Quint. 8, 3, 66: extrema, Sen. Ep. 12, 4.
Plur., Plaut. Capt. 4, 1, 4; id. Stich. 1, 3, 58: diurnae potationes, App. M. 8, 1.