Natsu: Yes
Gray: Yes
Gajeel: No
Laxus: No, Gray did
Jellal: Yes
Cobra: No, Sawyer did. One night stand. You both deeply regretted it in the morning (Sawyer, not so much. You, yes.) (before you got with Cobra)
Sting: HAHAHAHAno. Orga.
Rogue: HAHAHAHAHAHAHAyes.
Midnight: No. Some guy. He's dead.
Zeref: Yep.
Lyon: Yes
Loke: Nope. Bickslow. One night stand.
Rufus: Yeeee