Copulation
Methuna Sutta  (AN 7:47)

Then Jāṇussoṇin the brahman went to the Blessed One and, on arrival, exchanged courteous greetings with him. After an exchange of friendly greetings & courtesies, he sat to one side. As he was sitting there, he said to the Blessed One, “Does Master Gotama claim to be one who leads the holy life?”

“If, brahman, one could rightly say of anyone, ‘He leads the holy life without gap, without break, without spot, without blemish—perfect & pure,’ it would rightly be said of me. I lead the holy life without gap, without break, without spot, without blemish—perfect & pure.”

“But what, Master Gotama, is a gap, a break, a spot, a blemish of the holy life?”

“There is the case, brahman, where a certain contemplative or brahman, while claiming to be one who rightly follows the holy life, doesn’t actually engage in copulating with a woman but he does consent to being anointed, rubbed down, bathed, or massaged by a woman. He enjoys that, wants more of that, and luxuriates in that. This is a gap, a break, a spot, a blemish of the holy life. He is called one who lives the holy life in an impure way, one who is fettered by the fetter of sexuality. He is not freed from birth, aging, & death, from sorrows, lamentations, pains, griefs, & despairs. He is not freed, I tell you, from suffering & stress.

“Or… he jokes, plays, and amuses himself with a woman. He enjoys that, wants more of that, and luxuriates in that.…

“Or… he stares into a woman’s eyes. He enjoys that, wants more of that, and luxuriates in that.…

“Or… he listens to the voices of women outside a wall as they laugh, speak, sing, or cry. He enjoys that, wants more of that, and luxuriates in that.…

“Or… he recollects how he used to laugh, converse, and play with a woman. He enjoys that, wants more of that, and luxuriates in that.…

“Or… he sees a householder or householder’s son enjoying himself endowed with the five strings of sensuality. He enjoys that, wants more of that, and luxuriates in that.…

“Or… he practices the holy life intent on being born in one or another of the deva hosts, (thinking) ‘By this virtue or practice or abstinence or holy life I will be a deva of one sort or another.’ He enjoys that, wants more of that, and luxuriates in that. This is a gap, a break, a spot, a blemish of the holy life. He is called one who lives the holy life in an impure way, one who is fettered by the fetter of sexuality. He is not freed from birth, aging, & death, from sorrows, lamentations, pains, griefs, & despairs. He is not freed, I tell you, from suffering & stress.

“And, brahman, as long as I saw that one or another of these seven fetters of sexuality was not abandoned in myself, I did not claim to have directly awakened to the right self-awakening unexcelled in the cosmos with its devas, Māras, & Brahmās, with its people with their contemplatives & brahmans, their royalty & commonfolk. But when I did not see any one of these seven fetters of sexuality unabandoned in myself, then I did claim to have directly awakened to the right self-awakening unexcelled in the cosmos with its devas, Māras, & Brahmās, with its people with their contemplatives & brahmans, their royalty & commonfolk. Knowledge & vision arose in me: ‘Unprovoked is my release. This is the last birth. There is now no further becoming.’”

When this was said, Jāṇussoṇin the brahman said to the Blessed One, “Magnificent, Master Gotama! Magnificent! Just as if he were to place upright what was overturned, to reveal what was hidden, to show the way to one who was lost, or to carry a lamp into the dark so that those with eyes could see forms, in the same way has Master Gotama—through many lines of reasoning—made the Dhamma clear. I go to Master Gotama for refuge, to the Dhamma, & to the Saṅgha of monks. May Master Gotama remember me as a lay follower who has gone for refuge from this day forward, for life.”