Note 865 — BOOK II. BALLADS THAT ILLUSTRATE SHAKESPEARE.
Reading edition
Rashing seems to be the old hunting term to express the stroke made by the wild boar with his fangs. To rase has apparently a meaning something similar. See Mr. Steevens's Note on K. Lear, act iii. sc. 7, (ed. 1793, vol. xiv. p. 193) where the quartos read,
"Nor thy fierce sister In his anointed flesh rash boarish fangs."
So in K. Richard III. act iii. sc. 2, (vol. x. p. 567, 583.)
"He dreamt To night the Boar had rased off his helm."