Slow down my pace of jerking

I decide to slow down my pace of jerking my cock, as I feel a bit embarrassed to cum in front of Millie.

On the TV screen, the clip comes to an end, and Millie looks down at my cock with disappointment, slaps my shoulder, and says:

"How come you did not cum?"

"I wanted to see the entire clip, so slowed down in order not to cum and then it ended suddenly."

I reply, which is the truth, well, sort of the truth.

Millie gives me a smile and a suspicious look, then rewinds the clip to wear she reveals her big tits, then presses play.

Again the clip starts, and I see Millie's big tits as she squeezes them together on the TV screen, while real life Millie next to me is whispering in my ear:

"Cum for me Matt."

I am stroking my cock intensively, and Millie whispers in my ear:

"I want to see you cum Matt."

Then her head goes into my lap. For a few seconds I am hoping she is going to suck my cock, but instead she just blows air on it, creating a warm sensation with her breath, whispering about how she wants to see me cum.

Millie then rests her head on my stomach, my cock right in front of her face, still whispering:

"Give me that cum Matt."

I can feel I am getting close now, and her face is right next to my cock. Should I warn her?