A man wanted to marry a certain girl. So, he asked his grandfather:
''How would I know if my fiance is a virgin?'' 
The grandfather paused for a while and then replied:
 ''Go and look for a green and a blue paint.''
 ''Apply the blue paint on one side of your balls and the green paint on the other side then have sex with her.'
"If she tells you that she has never seen balls like yours then it will be clear to you that she has seen
many in her past".