Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
sup-palpor (subp-), āri, v. dep. n., to caress, fondle, or wheedle a little (very rare): occepit ejus matri suppalparier Vino, etc., Plaut. Mil. 2, 1, 28: suppalpandi nescius, Symm. Ep. 1, 84.