Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ex-stillo (ext-), āvi, 1, v. n., to drop or trickle out (very rare; not in Cic.): amurca exstillat, Col. 12, 50, 2: sinapis, oculi ut exstillent, facit, Plaut. Ps. 3, 2, 29: lacrumis, Ter. Phorm. 5, 7, 82.