Emily Wright, 31, introduces the code by saying it's all too common for men to "whinge" at their wives for being the sex police and "having no fun".
But according to Wright, they just aren't picking up on the simple cues and opportunities to have sex with their wives.
"Mums are willing, if you just approach it at the appropriate time," she says.
So when should they approach it? These four steps will show you.
1) When the kids have gone to sleep
Wright shows that 45 minutes after the children have gone to sleep is the optimum time to ask for sex.
"But there's only a short window" adds Wright.
After around one hour and 15 minutes after the kids have gone to sleep, mums get tired. And when mums get tired, that's the danger zone.
They definitely don't want to have sex in the danger zone.
2) Is the house tidy?
Messy house? Husbands - you're unlikely to have sex.
"When the house is spotless, you have a neverending opportunity. That is sex time," explains Wright.
"But also remember if she cleaned the house it doesn't count because she's tired because she's cleaned the whole house.
"If he cleaned the house it doesn't count because it won't properly be clean. It has to be a combination".
3) The hairdresser visit = likelihood of sex
Wright says if it's been five or six weeks since the wife has had her hair done, husbands have "absolutely no chance" of sex.
But there's a huge confidence boost as soon as she's visited the hairdresser, which will slowly decrease after about one week.
4) In vino veritas
"If mum has had no wine, you don't have a lot of chance."
Wright suggests the two-to-three glasses of wine mark is the peak amount of wine to approach for sex. After that, she's likely to fall asleep.
To end the video, the mum then brings out the "master chart" - a chart with all four lines drawn on them.
Where all the lines meet, Wright says that's when the best chance for sex is: that's when the kids have been asleep for 45 minutes to one hour and 15 minutes, the house is spotless, the two to three glasses of wine have been drunk and her hair has been done.
Do you agree with the "mum code" to sex?