Slip one over on somebody
Definition 1 of 2
Pro Tip 1/3Negative Connotation
The phrase often implies negative judgment towards the deceiver. 
She felt guilty after managing to slip one over on her friend.
Pro Tip 2/3Colloquial Use
Primarily used in informal situations among friends or in spoken dialogue. 
Isn't he sly? He slipped one over on the teacher again.
Pro Tip 3/3Caution with Usage
Be careful not to offend when accusing someone of this action. 
Are you accusing me of trying to slip one over on you?
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