RakeKay,
Loved reading your story of your first time draftng... reminds me of the days of yore when i was doing things like that for the first time. I think you are wise to ask about the manners relating to drafting... It is considered polite to ask the rider if it is ok if you draft. Just a simple "mind if i draft a bit?", or "may i just sit-in a while?" I've never, ever received no for an answer, but i have been in groups where, non permission asking drafters were dropped rickety-tick.

You were doing it right, if it felt easy in another's draft. Regarding shifting gears.. you may want to investigate a bit about cadence (frequencey of turning pedals, usually. described in rpm (revolutions per minute). Shifting to higher gears, lower gears should be done to maintain cadence relative to conditions.

When you were sitting in, and things got easy for a while, you were tempted to pass... it could have been that all you needed was that little break to rejuvinate your legs and off you go leaving this fella in your dust. However, back to politeness. I would consider that rude. If you are going to sit in and take a break, before you go off passing that rider in a blaze of your own ego, it would be polite to say "good mornign, how are you, thanks for the pull, thanks for the rest, have a great ride."

Sucking wheel then passing is appropriate for races, it is not for fellow riders you encouter out on the road or trail. Of course you can pass, but do so with a nod and a thanks.

Also, if you really are stronger and ready to go.. you might want to offer that they draft you a bit and take a small break.