Dic/ fall into

1. To descend or drop(,) freely or effortlessly(,) into something.
   To descend(,) or drop freely or effortlessly(,) into something.

• I was so tired that I went to my bedroom and fell into bed.

2. To come to assume a configuration, pattern, or order.

• The lines of text fell into neat rows.
• After a quick meeting, our plans fell into place. (cf. fall into place, click into place)

3. To come upon, receive, or become involved with something, esp. by chance.

• They fell into a lot of money unexpectedly, so they bought a new car.

4. To undergo a change of state or emotion, esp. a negative change.

• I took one look at my class schedule and fell into a bad mood.
• The tenants complained when the apartment building fell into disrepair.

.... The American Heritage® Dictionary of Phrasal Verbs