SB 10.33.30

naitat samācarej jātu
 manasāpi hy anīśvaraḥ
vinaśyaty ācaran mauḍhyād
 yathārudro ’bdhi-jaṁ viṣam
Synonyms: 
na — not; etat — this; samācaret — should perform; jātu — ever; manasā — with the mind; api — even; hi — certainly; anīśvaraḥ — one who is not a controller; vinaśyati — he is destroyed; ācaran — acting; mauḍhyāt — out of foolishness; yathā — as; arudraḥ — one who is not Lord Rudra; abdhijam — generated from the ocean; viṣam — poison.
Translation: 
One who is not a great controller should never imitate the behavior of ruling personalities, even mentally. If out of foolishness an ordinary person does imitate such behavior, he will simply destroy himself, just as a person who is not Rudra would destroy himself if he tried to drink an ocean of poison.
Purport: 

Lord Śiva, or Rudra, once drank an ocean of poison, and the result was that an attractive blue mark appeared on his neck. But if we were to drink even a drop of such poison, we would die immediately. Just as we should not imitate this pastime of Śiva’s, we should not imitate Lord Kṛṣṇa’s activities with the gopīs. We should clearly understand that while Lord Kṛṣṇa certainly descends to demonstrate religious principles, He also descends to demonstrate that He is God and we are not. That also must be demonstrated. The Lord enjoys with His internal potency and thus attracts us to the spiritual platform. We should not try to imitate Kṛṣṇa, for we will suffer severely.