BIG15
I received this email today. Although I can't copy the details to here, here are the main bits.
"Here’s additional 15% off for being a friend!"
Promo Code must be utilized by 24 December 2017.(GMT +8)
Promo Code is transferable.
Valid for travel from 15 January 2017.
Valid for on-line new prepay hotels indicated with "CV" icon only made through asiatravel.com
Promo Code must be entered at the payment page.
(I notice that they have had some recent, but now expired, 20% off promo codes, and so 15% may not be all that great)