The Difference of Two Squares

[S2 Maths - Special Algebraic Functions] This week's post is a little unique. The video as shown, is titled "The "Difference of Two Squares".

If you haven't caught onto it yet, the video's title is a triple entendre joke. Of course, explaining the joke is in bad taste, so I'll leave you to laugh at it when you do figure it out. (For those who need an explanation, a triple entendre is a phrase which can be interpreted in three different ways. Based on the content of the video, can you figure out the three meanings the video's title was alluding to?)