It is like a baby's arm holding an apple.

Anyone brave enough?

<ahem>........I don't know what type of book you are reading, but this quite common expression refers to how a man's penis looks when it is erect.

It is to draw attention to it's size, which in this case, is large.

Lordy lordy, how did I know it would be you!?

Because I've had it said to me so many times, I knew what it meant straight away.<insert wicked grin here>

Yeah but thats only when you were cradling a baby that was holding an apple.