An abbreviated form of 'totally'. Used in conversation because one syllable is better than three.
Barry: 'I am totes going to the party! It's going to be immense!'
Barney: 'Hells yeah!'
'I had an erection'
Used with the emphasis on the 'had' when something is a let down or has disappointed, especially when the speaker was very excited about the something in question. The point is that the erection is no longer there.
Billy: 'Dude, that show was totes
rubbish, I mean, I had an erection'
Bob: 'Homes, I know exactly what you mean. I'm totes