Thinking back to when i was 14, i was doing a youth project type thing. We had a party for the guys and girls, who were in seperate youth groups.
Girls kept picking Westlife, so i thought 'Fuck it' and joined in on one song. Showed i can sing when i want to. Later, a young girl about 10 or so picked Queen Of My Heart bless her, and she started the song singing quietly, and trailed off into silence looking petrified, so i jumped in and sang it with her. She gave me a little hug at the end.
No doubt that DHV to the rest of the girls there. And yeah, i die on my arse on occaision, can remember singing Boom! Shake The Room with a mate on a resort representative residential away with the college, he was drunk and started going brap brap brap and ruining it completely, making us both look moronic.
Best thing is not to rely on dutch courage, and try to interact with the crowd. And if you're a natural performer, even better.