The mummy blogger, who refers to herself as a "vegan breastfeeding mama", said her baby was "not involved", but simply "there".
She reiterated the point on This Morning, describing how her baby had been "very attached" to her at the time.
"I just like to share my life with others. Being an adult about the conversation: the baby was sleeping while breastfeeding and again, being an adult, I think we all like sex. It's totally fine.
"I know that people read titles and don't watch the video."
Holly then asked her if she has sex while her baby is awake.
She said: "Even if the baby is awake and off to side ... If the baby is OK, they're not judging you."
The hosts asked her if she's intimate with her husband in front of all her children, as she still breastfeeds her five-year-old son.
She replied: "It's not about being right or wrong. If you're having sex in front of your children and it feels right then it feels right.
"Do I make love in front of my eldest child? No."
When she was asked to clarify, Tasha continued: "Is it okay to murder someone in front of your children?"
Phillip quickly lost his patience and said: "If you did it in this country the social services would be on to you."
When Phillip then asked Holly's views on it, she didn't answer and went straight to the break.
The majority of viewers disagreed with the vlogger and took aim at her parenting style on Twitter.
One wrote: "Breastfeeding is fine. Breastfeeding while making love is not. If you baby wants feeding just stop making love."
Another posted: "Breastfeeding whilst having sex is just wrong! #ThisMorning Do one or the other!"
A third tweeted: "I'm gonna have to switch #ThisMorning off... no no no do not mix breastfeeding & love making together. Two special things keep separate!"
However others questioned whether Phil and Holly had been fair in their interview.
"Get the feeling Phil & Holly twisted the breastfeeding interview a bit," one said.
Another agreed: "#ThisMorning anti-breastfeeding campaign continues! If there's a controversy around breastfeeding they are on it."
- Daily Mail and NZ Herald