Graham replied: "Yes, I [had] a little bit. You know, just to try a little bit. It tastes good."
Holker replied: "No, I've never done that."
The model then admitted to having "squirted" her milk some distance.
She quipped: "Have you ever squirted it across the room? No? Is it just me?"
Elsewhere during the segment, Graham confirmed she had fallen asleep while breastfeeding.
She said: "Yes, definitely. A million times."
During her appearance on the show, the brunette beauty - who has long been a campaigner for body positivity - admitted she was pleased her own curves have been "starting a conversation".
She said: "It's about damn time my body is starting a conversation, I think we should be celebrating women of all shapes, ages and races. Whatever they identify as, I think that this is something that's really important.
"If my curves are going to start a conversation, let's keep it positive and let's let every other woman celebrate herself and her body. That's exactly what we should be doing, celebrate women for who they are."