思いつきレベルで恐縮ですが、こういう案はどうでしょうか。 — I'm sorry, this is just a rough idea, but how about something like this? (Workplace · Meeting, Polite to Colleague, JLPT N3)

Gesture & etiquette

Slightly tentative tone, open palm gesture as if presenting the idea on your hand. Look toward the meeting leader or the group, not just one person. Pause briefly after speaking to invite reaction.

Japanese meeting culture tends to expect polished proposals, so brainstorming sessions need explicit softening. 'Omoitsuki reberu de' (just a rough thought) signals that you're inviting iteration, not defending a position. 'Kyoushuku desu ga' (I'm sorry to impose) is the standard preamble for offering an idea that might not be fully formed. Without this softener, half-baked ideas can be received coldly.