It's not exactly a sex scene--or it depends on how you define "sex scene." We see Radcliffe's and Teresa Palmer's characters messing around, kissing, eventually starting to unfasten his pants, at which point the scene shifts to other happenings in another location. After that, we return to find Radcliffe and Palmer lying side by side; their dialogue makes it clear that they have had sex (she says she wants him to always remember her as his "first," to which he replies "Aw, no worries"). If you're looking to see any naked body, or actual action, that's not there at all.
