"I'm super emotional too. Healing takes time and it depends what birth you had... for me I've got a few stitches and stuff's going on so it's all painful.
"But [Vada] is absolutely beautiful and worth it."
Tiff said her and Ed's four-year-old son Arnold keeps questioning "why her tummy is so big."
"Bless him. He has no filter. He keeps saying: 'Is there another baby in there mum?' No. I'm trying to explain to him that it takes a long time for bodies to go back to normal and that it's hard."
The 37-year-old sent a sweet message of encouragement to other mothers who are struggling after giving birth.
"I just really wanted to say how important it is to bounce forward. And it's not easy to bounce forward and take the pressure off," she said.
"It's hard to accept it but you have to take one day at a time and you have to be kind to yourself. You can't let those negative thoughts enter the brain because everything the mind says the body hears."
"I'm sending love to everybody, especially those who have just had a baby, who are up late feeding, doing the brutal hours that newborn babies require."
Tiff's refreshing honesty and vulnerability comes three months after she urged mums-to-be around Australia to let go of the idea that they need to "bounce back".
Tiff described the look as "skinny legs and a perfect bump", but says that women – herself included – shouldn't have to deal with the unrealistic beauty standards around pregnancy.
"You don't have to have that toxic positivity [mindset] all the time where you're just loving every minute of pregnancy.
"Even after the baby's born, just take that pressure off and instead of bouncing back, bounce forward. Prioritise your own self-care and looking after that little baby instead of worrying about bouncing back."
Not only did she feel the usual expectations to look a certain way during that period, but Tiffiny had the added pressure of being a high-profile figure in the fitness industry.
"I had magazines calling me to do a 'bounce back' or 'comeback' feature when I was 38 weeks pregnant, and I was thinking 'oh my goodness, I'm meant to be thinking about my comeback'?" she revealed.