How to shave my groin.?

I asked this question before but the answer was pretty vague. This girl said to use a good razor, lot's of soap and to shave slowly. That's a great help but I could use some more details. What I want to know is should I shave in the shower? Because my girlfriend said the water could make my skin more sensitive and I already have very sensitive skin. Also should I go with the grain or against it? Finally I have tried to shave it numerous times and I have a terrible problem with irritation bumps even when I used my electric razor. Is there a way I could help prevent this? Like maybe rub lotion on the skin to make it soft? I look forward to answers so thank you very much to whoever answer's these questions for me.