Possible Clues:

• Inducing sleep
• Sleep inducing
• Sleep-inducing
• Soak takes crack (not Ecstasy), a sleep-inducing drug
• Inducing drowsiness or sleep
• Dough's in the making here, by the sound of it
• Inducing mental lethargy
• Concession opening shortly is likely to send one off
• That's enough to make one drop off
• New proof is put to ninety-nine, half-asleep