Good at whistling -> good at using lips/mouth or tongue for faux-whistling -> good at giving head to wife, presumably a pre-SRS trans woman or performing cunnilingus on wife if she is a post-SRS trans woman or a cis woman (haven't heard that called head before tho)
OP checks out honestly, I think whistling actually made me better at being able to form the optimal lip shape for that "hermetic seal engaged" feeling without giving my gf teeth surprises by accident. She's an even better whistler and her even briefly trying to give me cuni changed what I thought was possible to feel.
i mean i'd say i'm pretty good at whistling and i don't see how that'd be more than a basic benefit, like doing squats helps you be better at running but no matter how good you are at squats it won't automatically make you a great runner.