[f. BUMPER sb.1] a. trans. To fill (a drinking-vessel) to the brim. b. trans. To toast in a bumper. c. intr. (and with object it) to drink bumpers or toasts.
Hence Bumpering vbl. sb. (attrib. in quot.).
1696. W. Mountague, Delights Holland, 40. They [the Dutch] Bumper it but seldom.
1789. Burns, Whistle, viii. Ill bumper his horn with him twenty times oer.
1795. Wolcott (P. Pindar), Hair Powd., Wks. 1812, III. 301. Ye bumper it in Englands cause.
1808. Cumbrian Ballads, No. 75. 175. Come, bumper the Cummerlan lasses.
1859. M. Scott, Tom Cringle, xviii. 510. We all sang and bumpered away.