собаку съесть (на чем-л.) {informal} {v. phr.} {perf.}
so`baku s'est'
{literally} to eat a dog
To gain experience in sth. To be very experienced.
~ cut one's teeth on — ~ набивать шишки.
Он на этом деле съел собаку. — He has cut his teeth on (is very experienced in) this kind of tasks business./
See:
набивать руку