I saw a video once where at the bouquet toss, the bride acted like she was going to toss the bouquet, then turned around and walked it to her sister. Sister is touched, while they’re hugging, sister’s boyfriend gets on one knee behind her with the ring.

This is really the only way I see this going down. You better be extremely close to the bride or groom and either the bride or groom should be directly involved like this so it becomes part of the wedding as opposed to something totally unrelated. In this scenario, I think it works really well. It’s a special, happy moment that the bride gets to remember as part of her wedding, sister and fiancé get to celebrate their engagement at a beautiful, fancy reception with everyone they love around them, family gets to be there/celebrate. But everyone has to be exactly this level of on board for this to work lol.