Idioms and Phrases with come on in
come on in
Please enter, as in Come on in, the door's open. This phrase is simply a friendly request to enter one's house or some other place. The related come on in, the water's fine originated as an encouragement (or, sometimes, a command) to a reluctant or fearful swimmer but has been extended to other activities, as in Come on in, the water's fine—this is a great office to work in!