No. It's not OK after a transfer, though my doctor said sex is OK. It's actually only marginally a good idea at other times ... it can upset the natural ph balance in the vagina. Vaginal discharge is there for a reason, it cleans the vagina and keeps it fresh. Putting something in there is not so useful, no matter what the ads claim.
I wouldn't use it either. If you are dead set against discontinuing use I would call the RE and see if he gives you the 'ok'. Most clinics that I know of would say no for the reason Annie Brooks pointed out (PH).