Yes, this 60-year-old herbal tea shop does tell you to abstain from sex, but there is a reason behind.
First of all, this herbal tea shop in Kowloon City is quite hidden. It is underrated because it has a wide range of herbal tea drinks, 10 types plus turtle jelly and they are tasty.
Which one should you start with? Basically they are all healthy (of course). Here are some recommendations for you:
Summer time: try “Bun Dai Wung”(崩大碗） - Pennywort, refreshing and good for skin.
Winter time: try “Apple Pear Tea”（蘋果雪梨茶）- you know what they are. Good for lung and skin.
5 Flowers Tea "Ng Fa Cha"（五花茶）: improve eye sight.
Love-pes Vine "Gai Gwuk Cho"（雞骨草）: moistening the throat, refreshing lungs, removing heat, cooling during the summer heat and quenching thirst.
Begonia fimbristipula Hance Drink "Ji Bui Tin Kwai"（紫背天葵）: clear heat and digestion.
If you do not have preferences, you can try Begonia Fimbristipula Hance Drink "Ji Bui Tin Kwai"（紫背天葵）, because it is red, beautiful colour, with sweet and a little bit subtle sour taste, very refreshing.
Why do they tell people to abstain from sex? It is from the sign in the photo below which has a friendly remainder:
"People with flu should abstain from the followings:
Spicy; fried; or cold food; alcohol; cold drinks; coffee & milk tea; adults should abstain from sex.
It is because the background of herbal tea shop is related to Chinese medicine. The theory is if you are sick you should rest more, save more energy for recovery. That make sense right?