Explain The Warning Signs Of A Boggy Or Soft Uterus

Signs of Labour. // Resource Centres / Pregnancy & Babies / Giving Birth / The Postpartum Period / Postpartum: Physical Concerns. A floppy or boggy uterus.
So, I'm preparing for the NCLEX-RN. I'm doing practice questions from the Saunders CD and today I'm running through OB/maternity. I get this question, in a nutshell. What is your initial action when finding a postpartum patient with a soft, boggy uterus? The two answers that stand out are-- massage the fundus until firm, or encourage the mother to void. In my OB class, the teacher stressed to us to always first encourage the mother to urinate, or check for a distended bladder, before massaging the fundus. But Saunders is telling me that the correct answer is to massage the fundus first, and if that doesn't work, then to encourage the mother to void.
On the off chance that I get this question on the NCLEX, I will probably go ahead and answer 'massage the fundus', since that is what Saunders is saying. But I was wondering what you were taught about this? Ibm Serveraid Manager X3650 M2 on this page.