A verb in The Etymologies of the 1930s glossed “to lick (frequentative)” under the root ᴹ√LAB “lick” (Ety/LAB). Its derivation is not given, but it is probably from primitive *lab-ta, with the bt unvoicing to pt and then pt becoming to ps. This second sound change was abandoned by Tolkien in his later writings, so I’d avoid using this verb for purposes of Neo-Quenya, but you might use it if you assumed it was derived from *lab-sa. Alternately, you might use a different frequentative form like *laláva- or *lalappa-.