put nose in
put (one's) nose in(to) (something)
To involve oneself in an intrusive or nosy manner into something that is not one's business or responsibility. I wish my neighbors would quit putting their noses in and just leave us alone! Don't put your nose into your brother's affairs—he can manage well enough on his own.
put one's nose in (where it's not wanted)and stick one's nose in (where it's not wanted)
Fig. to interfere in someone else's business. Why do you always have to stick your nose in? Please don't put your nose in where it's not wanted!