Try pounding/dikdikin/dukdukon the oregano leaves so that its juices will be extracted. Add your calamansi and honey.
If you don't like the smell of the oregano mixture, try preheating a little bit the oregano leaves. Then ask someone to rub it to your back so that the leaves juices will be absorb in your back.
Don't use white shirts stains will remain.
RE: Wonderful Present From My Workmate