a leave behind
When you sleep with someone and forget to take your clothes, like your underwear, and then you have to go back just to get them because you’re too lazy to leave.
I left my pants on his floor. Now I have to go back just to get them.
Her bra is on my ceiling fan. I have to go back just to get it.
I left my boxers at her house. Now I have to go back just to get them.