[guppy]

Why would you ever lay -110 at Mansion? (Unless they are going to refund your losses of course.)

Place your bets on the exchange. As long as you accept the offers that are already up, it looks just like a regular sportsbook with reduced juice (no fees). E.g. right now you could play Denver -3.5 +100 or Rams +3.5 -105, compared to laying -110 each way in the sportsbook.