Be Prepare:
*knife
*lighter
*clear epoxy
*hot glue stick
*ice cream stick/small stick(use for mix epoxy & applying epoxy)

Parking sensor dropped inside bumper
1; I use hot glue to stick to parking sensor if u can
2; use the hot glue push the sensor into bumper(make sure the glue is stick properly)
3; mix the epoxy even use a small stick like ice cream stick apply in it.
4; softly pull the hot glue sensor to stick with the epoxy. Hold it for a min atleast. Then pull out the hot glue.
5; clean the epoxy glue with a clean towel the next day. Because u need to let it dry for whole day..