SB 3.31.38
balaṁ me paśya māyāyāḥ
strī-mayyā jayino diśām
yā karoti padākrāntān
bhrūvi-jṛmbheṇa kevalam

balam—the strength; me—My; paśya—behold; māyāyāḥ—of māyā; strī-mayyāḥ—in the shape of a woman; jayinaḥ—conquerors; diśām—of all directions; yā—who; karoti—makes; pada-ākrāntān—following at her heels; bhrūvi—of her eyebrows; jṛmbheṇa—by the movement; kevalam—merely.
TRANSLATION

Just try to understand the mighty strength of My māyā in the shape of woman, who by the mere movement of her eyebrows can keep even the greatest conquerors of the world under her grip.

When scriptures repeatedly talk about something, it means that those are the places where the sadhaka has got tremendous chance of deviation. Therefore, the scriptures, acting like a well-wishing friend, like a caring parent warn us. I remember in my childhood days, my parents would never allow me to watch cartoons, because they knew if I watch, I will become extremely dull. Also, when I would alone want to go on bicycle on highways, they would be extremely vigilant to warn me about the necessity of driving safely. Similarly, the scriptures of which Srimad Bhagavatam is non-different than Krishna Himself caution us like a loving mother. Scriptures tell us the truth without letting us feel bad about it. If some person says us the same thing, we may feel disgusted or we may detest that person. Sastras do that job very proficiently. Especially, there are two things of the many things that the entire Srimad Bhagavatam warns us about – One is the danger of the association of opposite sex and those attached to opposite sex, and another is the danger of Vaishnava aparadha. And positively, it talks repeatedly about the glories of the Holy Name and serving Lord and His devotees.

Why is the danger of association of opposite sex so much highlighted in the scriptures? What is that exact danger? Srimad Bhagavatam tells us,
puṁsaḥ striyā mithunī-bhāvam etaṁ
tayor mitho hṛdaya-granthim āhuḥ
ato gṛha-kṣetra-sutāpta-vittair
janasya moho ‘yam ahaṁ mameti
The attraction between male and female is the basic principle of material existence. On the basis of this misconception, which ties together the hearts of the male and female, one becomes attracted to his body, home, property, children, relatives and wealth. In this way one increases life’s illusions and thinks in terms of “I and mine.” SB 5.5.8

The expansion of illusion, or multiplication of desires that it brings forth in the heart cannot be compared with anything else. And one feels happy in that illusion.

Also, it tells us,
na tathāsya bhaven moho
bandhaś cānya-prasaṅgataḥ
yoṣit-saṅgād yathā puṁso
yathā tat-saṅgi-saṅgataḥ
The infatuation and bondage which accrue to a man from attachment to any other object is not as complete as that resulting from attachment to a woman or to the fellowship of men who are fond of women.

The above verse is being spoken by Lord Kapila to His mother Devahuti. Same verse also comes in the Uddhava Gita (SB 11.14.31), where Lord Krishna is personally warning Uddhava just at the end of a section describing the glories of pure devotional service. Lord describes the entire chapter of Aila Gita just so that we can be saved from falldown by associating with a woman. If one is just conscious of Krishna but not cautious of maya, one may become an easy victim of maya. Therefore, one aspiring the celibate order of life must repeatedly read these sessions. Caution has already been raised by the sastras, and if one falls prey to them, only we will be held responsible.

Therefore, one must give up the association of opposite sex in any form including seeing at them, joking or talking with them etc. and cultivate positive attachment to the association of devotees. This having done, the devotee can free even his mind from the clutches of opposite sex. Shrila Prabhupada had a disciple named Upendra who was staying with a young girl. He told Prabhupada he wasn’t having any kind of connection with her. Prabhupada said, “Where there is a boy and there is a girl, there is sex.” Prabhupada told him to leave that place and stay with him. Being delighted, Upendra left his old place and went to Prabhupada’s apartment. Seeing and observing Shrila Prabhupada and taking his association, Upendra found his attachment to the opposite sex dwindling. If one takes strong association of devotees, one attachment to opposite sex will loosen.