Little head feeling is the same for me. It helped more during mediocre sessions, where I otherwise would've went limp at a lull in the session. Essentially I stayed hard with less stimulation. Not sure if I'm accurately stating this, but the same muscles used to keep my erection going also drive me toward ejaculation. Obviously other factors involved, how turned you are, how long since last ejaculation, etc. In a session with an ATF, where I feel great and am turned on, the medicinal benefits were not needed. In fact sometimes I deliberately went without any pharmaceutical aid so I wouldn't feel dependent.
Big head feeling often included elevated body temp (not by a lot but noticeable), headache, or dehydration. So the V pills I had were 25mg, which I think was lowest dose available at the time, I was cutting them in half, but one time I took a full 25mg pill - I didn't know what facial flushing was before that day, but if felt like I had a 106 degree fever, concentrated in my face. Good thing thing with V is it wears off after a few hours, although the guys going to hospitals with 10 hour erections may say otherwise. Later I tried 10mg cialis, I was taking it the night before a session and sometimes would wake up with body ache and/or headache. Since then I've switched to 5 mg and take it in the morning, stay hydrated, and no side effects.
Last but not least, I'm an odd dude with decades of baggage, bad decisions and other hang ups to work through. These hour long getaways from the soul crushing rat race are about the only pleasure in life I truly cherish. So I try to maximize that pleasure best that I can. I certainly wouldn't expect my experience to be the norm, so take everything I say with a boulder of salt