'No' and 'Not yet' are such important words

My son, pay attention to my wisdom,
listen well to my words of insight,
2 that you may maintain discretion and your lips may preserve knowledge.
3 For the lips of an adulteress drip honey, and her speech is smoother than oil;
4 but in the end she is bitter as gall, sharp as a double-edged sword.
5 Her feet go down to death; her steps lead straight to the grave.
6 She gives no thought to the way of life; her paths are crooked, but she knows it not.

7 Now then, my sons,listen to me; do not turn aside from what I say.
8 Keep to a path far from her, do not go near the door of her house, 9 lest you give your best strength to others and your years to one who is cruel, 10 lest strangers feast on your wealth and your toil enrich another man's house. 11 At the end of your life you will groan, when your flesh and body are spent. 12 You will say, "How I hated discipline! How my heart spurned correction! 13 I would not obey my teachers or listen to my instructors. 14 I have come to the brink of utter ruin in the midst
of the whole assembly."

15 Drink water from your own cistern, running water from your own well. 16 Should your springs overflow in the streets, your streams of water in the public squares? 17 Let them be yours alone, never to be shared with strangers. 18 May your fountain be blessed, and may you rejoice in the wife of your youth. 19 A loving doe, a graceful deer--may her breasts satisfy you always, may you ever be captivated by her love. 20 Why be captivated, my son, by an adulteress? Why embrace the bosom of another man's wife?

21 For a man's ways are in full view of the LORD, and he examines all his paths. 22 The evil deeds of a wicked man ensnare him; the cords of his sin hold him fast. 23 He will die for lack of discipline, led astray by his own great folly. (Proverbs 5:1-23)

A son should be taught that the sexual hunger he has is a gift from God - and that he doesn't get to eat for several more years. This requires the inculcation of self-control, but parents do not have to wait until their son is in the grip of sexual temptation before they may instruct him on how to respond to it.
There are many other areas requiring self-control where this virtue can be acquired and made habitual from the time their son is a small boy....
Many parents try to teach their sons about sexual self-control after sexual temptation becomes an issue. But sexual self-control is just one species of the genus 'self-control.' Sexual self-control is simply a subset of self-control. Parents should be inculcating self-control first, throughout the son's life.When a boy starts whining, and tries to demand something, and the parents say: 'No' they are teaching self-control. This becomes a habit established in his character long before adolescence arrives. When sexual temptation first arrives, the necessary response of self-denial must not be an entirely new concept. If parents indulge a little boy's emotions, his whims, his tantrums, then what is going to happen to that young man when he becomes consumed with sexual desire? (p39-40)