chisel in
verb1
To barge in on something; to be a third wheel; to insinuate oneself into a situation or relationship; to get oneself involved in something.
- Ignore him, he's only here because he chiseled in.
2
Slang To unfairly push in on (something); to gain a role in (something unsavory); to acquire a partial interest in (something) through deceit.
- He's chiseling in on our operation.