In Thai, we have an idiom "ปิดทองหลังพระ" (Pid Thong Lang Phra) that refers to the placing of a sheet of gold leaf on a Buddha statue to pay respects at a temple. Instead of putting it on the front where everybody sees it, you put it behind where nobody sees it. Thus it means doing something good without flaunting it.
However, if you purposely let everyone know you're putting the gold sheet on the Buddha's back, it can't be considered as "ปิดทองหลังพระ".