Nitrous oxide does cause your tongue to become slightly numb (Nitrous is used in larger quantities as a anesthetic , so that makes sense) Therefore gives a smoother mouth feel. Also like Nitrogen (or Argon) it comes out of solution slower than CO2. This gives smaller, smoother bubbles in the head. I think Guinness uses Argon to get this effect.
For small batches you can use an isi whip.
(What they use in star bucks to whip cream).
Which uses small canisters of Nitrous oxide.
(See here for more things you can do with an isi whip)
You could also do this on a large scale with a larger tank of Nitrous oxide.
How ever you need to provide documentation to show what you are going to use it for.
(I.e., you are a medical practice, you use Nitrous for drag racing, you are a large bakery etc)
So unless you can ask a friendly petrol head to borrow some (make sure it is food grade though), it will probably be difficult to do more than one litre (isi whip) without going up to commercial scale.