Possible Clues:

• Secrecy, with 'the'
• 'Up top!' follower
• U-turn from "up high" (2 words)
• Follow-up to "Up top!"
• What discreet acts are done on, with "the"
• What discreet acts are done on, with 'the'
• On the (discreetly)
• On the -- (secretly)
• On the -- (discreetly)