sow (one's) wild oats
To engage in rebelliousness or promiscuity, typically in one's youth before settling down. Bill and I had to break up because I was looking to get married, and he just wanted to sow his wild oats. You can't sow your wild oats forever! Soon, you'll want a wife and a house, and you'll regret the things you're doing now.
sow one's wild oats
to do wild and foolish things in one's youth. (often assumed to have some sort of sexual meaning.) Jack was out sowing his wild oats last night, and he's in jail this morning. Mrs. smith told Mr. smith that he was too old to be sowing his wild oats.