What is "to claw one on the back"

Claw \Claw\ (kl[add]), v. t. [imp. & p. p. Clawed (kl[add]d); p. pr. & vb. n. Clawing.] [AS. clawan. See Claw, n.]

1. To pull, tear, or scratch with, or as with, claws or nails.

2. To relieve from some uneasy sensation, as by scratching; to tickle; hence, to flatter; to court. [Obs.]

   Rich men they claw, soothe up, and flatter; the poor they contemn and despise.
   --Holland.

3. To rail at; to scold. [Obs.]

   In the aforesaid preamble, the king fairly claweth the great monasteries, wherein, saith he, religion, thanks be to God, is right well kept and observed; though he claweth them soon after in another acceptation.
   --T. Fuller

   Claw me, claw thee, stand by me and I will stand by you; -- an old proverb.
   --Tyndale.

   To claw away, to scold or revile. ``The jade Fortune is to be clawed away for it, if you should lose it.''
   --L'Estrange.

   To claw (one) on the back, to tickle; to express approbation. (Obs.)
   --Chaucer.

   To claw (one) on the gall, to find fault with; to vex. [Obs.]
   --Chaucer.