Kissing scenes are shot just like any other scene in both industries like this:
The crew deals with the lights, sound, decor etc. while the director and cinematographer might have one last chat to finalize the angle of the shot. Once everything is decided the actors will be put in their places and do the scene for how ever many takes till the director is happy. I don’t know about Bollywood, but in Hollywood the actors drink some alcohol to loosen them up a bit if needed. They really do kiss each other in Hollywood, for Bollywood not so much though that’s changing recently. If the actors really don’t want to kiss each other but the script demands it then there are certain angles where it looks like they’re kissing but actually aren’t which is most common in Korean dramas. Depending on the actors though they might look great or extremely awkward.