Speaking into the bag
News News blog
To speak into the bag means to say something at random.; to say something without giving it much thought.
Speaking into the bag - this phrase is often used as a preemptive excuse when you have a suggestion on a topic but haven't really thought about it in depth and the idea turns out to be a misjudgement or untenable. This way you can avoid embarrassing yourself with your idea. The saying originated at the end of the 1990s.
However, it remains unclear which bag is meant. Possibly a rubbish bag - in case the ill-considered proposal is rejected by everyone else.