A kiss is when multiple people mash their lips against each other.
People will often do this for an extended period of time. Most incels have never kissed.
What does it feel like?
Many kiss virgins understandably think kissing women would taste good and maybe even like candy, however kissing actually feels no different than touching raw chicken breast with your lips. The only thing that makes a kiss feel good is the value applied to it internally.
Purpose of kissing
Humans kiss partly as a way to determine compatibility via saliva bacteria. If your dates bacteria, "gels", with your unique saliva bacteria profile, your immune system reacts positively, you feel good, and want to kiss more. Humans also kiss as a way to signal caretaking, as we inherited our animal ancestors tendency to feed each other via the mouth. Except we don't exchange food when we kiss, usually.