(a non-comprehensive guide)
In the Evening
Do not drink too much. While staying hydrated is important, you don't want to go to the toilet every few minutes or so. This would be even worse in a shared flat, where you probably can't afford to run into one of your fellow lodgers. If you absolutely have to go to the bathroom, or kitchen, or whatever, put over a large sweater and sweatpants. Hope that you won't get busted.
Make sure you have eaten juuust the right amount. That is, not stuffing yourself.
Do not forget to be excited when zipping the suit.
Do what you would usually do. If you feel tired, lay down. Remember to keep fresh bed sheets around, since the sweat you are going to produce at night will not have that many places to go.
Keep the occasional water bottle in reach.
At Night / While in Bed
Take some measures for a well-balanced body temperature in bed. Don't pull the sheets down too much, because you are going to freeze when your body powers down while sleeping. But don't completely roll yourself up either, since that will lead to way too much sweating, which tends to get very disgusting if it cools down.
Touch your dick*, if you want to. Like… you are all by yourself. Nobody gives a shit, and nobody to give a shit is there anyway. Seriously, do it, it feels amazing!
Try to fall asleep. If you can't, it might be a good idea to get out of the suit and try it on again on another occasion. Your skin will thank you.
In the Morning
Get up and masturbate. Then, get the hell out of that suit.
* Minor difficulties might be experienced if you are female.