The Bhagavad-gita describes that by contemplating on the object of the senses one develops attachment, from attachment then one starts to develop lust and this way desire, illusion, anger, fall down, everything comes one after another.
So he was there meditating with his half opened eyes, and the object of the senses drew his senses, and then, I am sure that we will see how step after step, how he becomes conquered by the senses. So, this should give us all a good example how we have to at the very root of thought, root of the desire, we have to control the mind, and continually bring the mind back to Krishna. Its very hard for this yogis when they simply meditating on the nose.
H.H. Jayapataka Swami Maharaj
1983, 24th June, SB class @ Miami, USA