butt into (something)
To interrupt something (which is stated after "into"). I'm sorry to butt into your discussion, but I have some information that might help. Mom is always using the phone in her office to butt into my conversations!
butt into something
to intrude upon something; to break into a conversation. Please don't butt into my conversation; I'm on the phone. I don't like my conversations being butted into by perfect strangers!