nibble (away) on (something)
1. Literally, to eat something at a slow pace and in small bites. I wonder if Mary isn't feeling well—she only nibbled on her dinner. He sat on the bench, happily nibbling away on his cookie.
2. To bite something very softly so as not to break the surface. He started nibbling on my elbows, thinking it would turn me on.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
1. To eat something by taking small, quick bites, often as a snack or a light meal: Dinner wasn't for another two hours, so I nibbled on some potato chips. The rabbit nibbled on a carrot.
2. To bite something but not break the surface: Nervously, I nibbled on my pencil's eraser during the test.
The American Heritage® Dictionary of Phrasal Verbs. Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.