I don't know any idiom with these two words.

It is in a story I have for homework about walking & using the cell phone at the same time
here is the sentence

Otro experimento reveló que quienes hacen ambos cosas a la vez tienden a no notar objetos en el piso (vómito falso, una bota).

Another experiment revealed that those doing both things at the same time tend not to note objects on the floor (vómito falso, a boot)

I did google it & there are plenty references but I don't understand them since they are in Spanish.

fake vomit? (which someone put there to test whether they'd notice)''

I still don't quite get what do they mean by a "false vomit" (either it is, or is not), but that's how I interpret it personally.

that's what i'd think too.. the gag plastic vomit

Hi Motley
There are numerous videos on YouTube where youths are being sick in public with what I assume is false vomit. I suppose they are trying to generate some sort of reaction. Don't know if this has anything to do with your post.

That was my thought lazarus, either it is or it isn't, but I think Valerie, dandi & Eddy have it. I guess my 80 year old Cuban teacher is more up to date than I am. je,je,je
I'll check out U-tube

as Dandi and Valerie said I think it is like a joke

like a picture or something just to say that there's something on the floor

I checked out U-tube, I didn't see anything falso, disgusting.

Some of them were for real, but I am convinced others, particularly when there were plenty of people around, were false.

What's becoming of the younger generation, or are we just getting OOOLLLDDD.

Motley, it's an experiment, a study, and the people conducting the experiment put things on the sidewalk to see if people talking on the phone would notice them. The two things they used were fake vomit and a boot.