I have taken it quite a few times - I will answer your questions
1. Has anyone used viagra before to try and treat a case of performance anxiety? Were you successful?
It will work for this, if your sexually aroused (mentally) then expect to get hard. (I personally have not used for this reason)
2. Has it still worked after consuming small or large amounts of alcohol? I know it's not really recommended to have with alcohol and I don't plan on being heavily intoxicated while using it, but most likely will have had 2 or 3 drinks.
Yes - if you suffer from 'limp dick, crystal dick, stim dick, brewers droop' etc Viagra will still work for you.
3. Quite a lot of stories I've read on various websites say it's helped prevent cases of premature ejaculation, and if anything it's made it almost too hard to come. This apparently stems from it becoming less sensitive during sex, which make sense. Is this the case in general?
Yes! It is usually pretty difficult if not impossible to cum when on viagra. It takes a lot of stimulation to make you cum.
4. I am debating whether or not to tell my next partner if I'm using it beforehand, I'm thinking I probably won't, and then tell her some time afterwards. I guess I could just see how I go without it at first and then have some if it's not happening, but my confidence is pretty shot in this department to the point I just know it isn't going to work (I know, bad mindset, very hard to change though). Ladies: what would you think if you were with someone for the first time and they told you later they had used viagra?
Tell them, they may need to use extra lube - buy a magazine to read when your banging away etc.
Please remember that Viagra comes with a lot of side effects - stuffy nose / blocked sinus (that can become very uncomfortable, more sore if your mouth is full), increased body temperature, facial flushing, really bad head, increased blood pressure, the ability to spring an unwanted boner the day after on public transport (found that out the hard way-pun intended).
Be very careful if mixing with stims, MDMA, G, Ket etc and remember that if your using Poppers you can collapse, have a heart attack etc