After a while the G's are kind of addicting. The USAF starts G tolerance training all the way in T-6s, at least at Sheppard, with an aerobatic and formation syllabus that is more complex and demanding than the Navy version. Just different priorities in how they flow the training. Then in T-38s you're pretty much expected to be able to sustain in and out of 4-6 G's throughout exercises that can last over a minute. The Gs in a real plane will make you tired and most likely embarrass you as you struggle just to stay awake and get that LAST SIP OF AIR FOR THE LOVE OF GOD!!!!! while your IP is happily chattering away critiquing your maneuvers, but over time your body will simply adapt to the point where you're able to think and maneuver under G loads without even thinking about the Gs. Get on your G strain BEFORE pulling the stick back, and over time you'll learn to not over-strain so you won't wear yourself out in the first 5 minutes unnecessarily.
Of course, be smart about it. Make SURE your posture is good in the seat, and just because you may be strong enough to move and twist under G's doesn't mean you *should*. I had VERY strong core muscles during F-15E FTU so I could be pretty mobile in the cockpit up to about 6.5 Gs. And then in the last advanced air to air maneuvering portion of the course, I herniated my L5-S1 disc being an idiot moving around while pulling Gs instead of just centering myself, picking a direction to look, then not moving until I unloaded. Oops, and now I've been living with that injury for almost 20 years, which made my flying career both shorter and less enjoyable than it could have been.
And for the sake of your family and friends, if your G-warmup doesn't go PERFECTLY, tell your flight lead and restrict your maneuvering for the rest of the sortie. I've seen at least a dozen HUD tapes of dead fighter pilots who weren't feeling quite right, recently returned from leave or illness, or who everyone noticed wasn't quite on their game that day, or even in their own hud recording was clearly struggling during the G-X warmup, but they didn't back off the sortie profile and died because of their big fat G-LOC'd ego. If you can't hack the G-X, do another one to wake yourself up. If the second one doesn't go well, confess your pitiful weakness that day and live to try it again next sortie. And NEVER hesitate to go back to basics if you gray out or black out. Unload to get your vision back, and do your best nose low/high/inverted recovery to level flight and call knock it off.