You Can Tell By More Than A Few Reasons. One Is That You Would See It Sticking Through His Pants. Another Is That He May Become Shy And Embarrassed All Of The Sudden, But Do Not Confuse This With Behavioural Shyness If They Are Shy Constantly. These Are Only Two Examples Though...
Depends. How tall a guy really doesn't have to do with how big his penis is, that's a completely different set of genes.
Depends on how big their boners are. Maybe I doesn't (PENIS)
Because they can see how big and if they are nice enough to suck
Well Boys are the males and girls are females xD! I CANT TELL YOU :X
Some do, some don't, the average penis is 6inch for an adult.
Without measuring it or asking the owner you can't.
Boys have big fins girls are small and have small fins =)
Well if you have big penis and you know what your doing just push right in? Idkk.
well some boys dicks are big when there a baby and its a common thing
it will tell you on the box or ask the pharmacist, they will help you.
a penis
If they are decorated (women). If they are not decorated then they are boys. If they have big rims then they are girls and if they are small rims then the are boys.