1. I've listened to all sorts of music while tripping, jam bands, trance, house, Peruvian soul, Zambian rock, electronica, a wide range of great music, but nothing compares to the incredible sound and bizarre and insightful philosophies of life of ABBA

. Really anything with a pleasant or interesting sound is good, I'm not a fan of music that's hard while tripping but I also don't like music that's hard while sober. If you like (small) orchestral music at all consider Olivier Messiaen's Oiseux Exotiques.
3. I hold mine under the tongue for a while but I'm pretty sure it's mostly superstition and that if you put blotter in your mouth you're going to trip no matter what you do next.
4. I love that feeling, it sort of reminds me of the moment before an orgasm.
5. I'd save the weed for the end of the trip, but it can be great then.
As for significance it's not like you'll find career plans written on the back of the tabs. Just deconstruct the moment, where are you, how do you feel, who are you with, and go with the flow from there. Think about what you see that's important to you and what you see that isn't, and examine your values. Maybe you'll just end up laughing for a while, that's good too.