About what thing this joke is?
I watched youth comedy and 2 young guys talked.
- Oh, can I have these? (about shoes). These are way too big.
- You know what they say. Big feet...
And they all smiled.

What do English speakers say about big feet?

Question

About what thing this joke is?
I watched youth comedy and 2 young guys talked. 
- Oh, can I have these? (about shoes). These are way too big.
- You know what they say. Big feet...
And they all smiled.

What do English speakers say about big feet?

Answer

Big feet, hands, and height are often joked as meaning it's more likely they have a big dick.