In an inconspicuous, not easily noticeable, manner.
1That maid said she bought it on the sly all the time.
2I think sometimes he runs away and does it on the sly.
3He watched her on the sly as she moved about the room.
4Half the time Jeff bets against his own horse, on the sly.
5Cleopatra, have you been in the kitchen drinking milk on the sly?
6There, drinking is rather an aristocratic indulgence, enjoyed only on the sly.
7I've always imagined that he may have written poems on the sly.
8How Madame Valière must have gorged on the sly, the rich eccentric!
9However, the banking details used for this process were changed on the sly.
10The age group that's most likely to keep financial accounts on the sly?
11It's come to the point where you drink on the sly.
12People read his book on the sly and talked about it in whispers.
13She did some on the sly-ina scared kind of way.
14Tonight the cook was too busy to approach on the sly.
15I'd planned to get out on the sly tonight, while in here officially.
16Maltese Knights and Maltese cats do their killing on the sly.