Six plus three

[sanath ekanayake]

Boy is making fun of his girl friend and says to her in a poem,

"Six plus three is nine,
I can enter in you but you cant enter in mine".

Girl instantly replies,
" Five plus four is also nine,
I can measure your length

but you can't measure the depth of mine"

 

[roxter]

 

[Vishwalisha]

 

[cking]

W@ is the meaning of "Six plus three is nine"?? are there any double meaning?