[The stem of SPLASH v.1] In a splashing manner; with a splash or splashing sound.

1

1795.  Scott, William & Helen, xlvii. Tramp! tramp! along the land they rode, Splash! splash! along the sea.

2

1841.  Lytton, Nt. & Morn., V. i. The full flood of sound … came splash upon him.

3

1895.  Outing, XXVI. 30/2. Spat-spat, splash! they fell.

4