dig into

1 :  to mix (something) into (soil) by digging dig the compost into the soil

2 informal :  to begin eating (something) The family was digging into a delicious meal. They dug into their steaks.

3 somewhat informal :  to try to learn or uncover information by studying (something) The detectives dug into his past and learned that he had once lived in another country.

4 :  to push against (a body part) in a sharp and painful way The bed's springs are digging into my back. Her fingernails dug into my hand.

5 :  to push (something) into (a body part) in a sharp and painful way She dug her fingernails into my hand. He dug his elbow into my ribs.