To make it a little easier, let's define the opposite of normal. What is not normal? When a person is fully aware of their actions (and all the possible consequences in a particular situation) and the said person harms (either physically, psychologically, financially or all of the above) himself/herself or someone else in a way that it cannot be easily forgotten or the damage cannot be easily reversed (within minutes), then it's obviously not normal. Everything else is pretty much normal, be it dancing in a shower covered in butter or licking someone's eyeball (assuming they agree with it). In short: do whatever the hell you want as long as it does not bring any harm.