Laying eyes on an incredably hot girl, who is just a little bit too young for you, and expressing your sexual interest with a "Sweet Jesus!!"
Sitting outside the pub and a group of scantily clad 17 year old girls walk past. Someone pipes up "SWEET JESUS!..." and everyone looks round to have a gander.
The "Holy Shit!" reaction you get when you scare the crap out of someone (or your pet cat).
Sweet Jesus! Where in the hell did that come from!
Giving or receiving oral sex while saying the lord's prayer.
Our Father who art in heaven,
hallowed be thy name.
Thy kingdom come.
Thy will be done on earth, as it is in heaven.
Give us this day our daily bread,
and forgive us our trespasses,
as we forgive those who trespass against us,
and lead us not into temptation,
but deliver us from evil.
and there you have it you just preformed a Sweet Jesus