[Tristan Lall]

You might find it called "pipe dope" or "pipe thread sealant" or some such thing. Depending on the type of fitting, and on how often it is removed and replaced, that may be a viable option. It goes on messy, and doesn't really dry (like a glue would), but forms a airtight seal between the threads. As always, apply it sparingly, and don't let any get inside of the fitting (just on the thread surface).

Note that neither pipe dope nor teflon tape are appropriate for some high pressure fluid lines (like hydraulics)--that shouldn't be a problem for FIRST, but in the "real world" you may encounter dry compression threads (e.g. tapered plugs on hydraulic systems).