The phrase "dull side" refers to the less interesting, boring, or unexciting aspect of something. It implies that there is another side that is more engaging or exciting.
Sentences with «dull side»
3 Coat dull side of non-stick foil with cooking spray. (vegetariantimes.com)
Besides a few dull side quests and some technical hiccups, there's not much I can criticise about Assassin's Creed Origins. (useapotion.com)
TIP: I use an extra long piece foil to cover a 13 × 9 pan, turn pan upside down lay foil over bottom to form another pan, (dull side up) then insert this into the baking pan. (ohmyheartsiegirl.com)