Don't keep secrets as a crew, especially if you feel uncomfortable with actions. Be tactful in your debriefs to bring things you thought you could work on. Yes if something happens debrief after shutdown. Openly discuss things you would ASAP as a crew before doing it. Be honest, be upfront but tactful. If you feel you need ASAP as I means of correcting an Unsafe situation that you can't talk directly to your Captain or FO about....I'd argue that is beyond ASAP and warrants a call to your chief pilot and crew scheduling for reassignment. On the other hand if you are worried about hurting someones feelings (the PIC) and just ASAP as a means to get get information out there...I'd argue you need to be better at debriefing and being a better crew member. Own your mistakes....and approach everything as a crew. At the end of the day EVERYONE makes mistakes and we ALL are always learning.