Find the IP Address of an iPhone or iPad

Getting an iPhone or iPads IP address is fairly straight forward, and the instructions are the same for basically all versions of iOS. From the devices home screen:
- Tap on the “Settings” icon and navigate and tap on “Wi-Fi Networks”
- Find the network name of the router you are currently connected to, and tap on the blue arrow button next to the active networks name
- Assuming you are usually a DHCP address, scroll down and find the IP Address in the format of x.x.x.x, for example 192.168.1.2
If your iOS device is using a manually set static IP address, or BootP, you can just tap on those tabs to access that information instead.

Knowing the devices IP address is useful for a variety of things, from adjusting bandwidth settings on a router, to transferring files directly, to using SSH to connect to an iPhone.

Ah! But what about their IPv6 addresses?
It’ll dish out the IPv4 addy
[...] the Terminal or your preferred SSH client, find the iOS IP address, and connect to the iPhone using SSH [...]
The problem is that the IPs are dynamically assigned. I want to freak a friend out by telling him his Longitude and Latitude randomly (he’s on the road a lot).
The system has to be able to find the phone; it has to be possible.
How?
~H~
The IP adress box is empty on my Ipad 2. I dont have any cellular data on my Ipad. Can someone help me?