Musar על עירובין 108:4

CLINGING: The matter of clinging is when a person's heart clings so much to the blessed G-d that he ceases to turn or take interest in anything else but Him. This is what Shlomo brought by way of analogy: "a lovely hind and a graceful doe, her breasts will satisfy you at all times; you shall always be infatuated with her love" (Mishlei 5:19). And in the Talmud, our sages, of blessed memory stated (Eruvin 54b): "It was said of Rebbi Eliezar ben Pedat that he sat and studied Torah in the lower market of Tzipori while his cloak lay in the upper market of the town". The ultimate goal of this trait is for a person to cling thus to His Creator at all times, and at every moment. But at the least, if he loves his Creator, certainly he will cling to Him in this manner during the times of his [divine] service.