Well, I don't have practical tips for initiating, but on the topics of french kissing itself..
oh, and like everything, it's only a guide line, if the girl likes it a bit different, it's no use to rigidly do these things, but they kinda work as a 'default'. Well, at least it works for me. I've been told I'm a good kisser, so..
1) Don't open your mouth all the way. It's no fun to get a mouth full of spit, or drool all on each others faces. Try to 'match' the lips so to speak.
2) Close your eyes, it's rude to stare
3) Kissing is like talking, you each take your 'turn', when it's your turn, apply some gentle force, when it's her turn, you withdraw a little bit. However, some girls aren't good at taking charge, so if that is the case, no big deal.
4) Going on with gentleness, don't pucker your tongue like a rod and 'tongue rape' her, that's no fun. Start out gently, exploring each other's mouth, lett the passion build rather than going into frenzy at the first moment.
5) Things NOT to do: running circles with your tongue in her mouth, also know as the 'dishwasher', or chewing air, aka 'the goldfish'. Most girls find this a turn-off.
6) Don't neglet your hands! Hug her, caress her, good places are: the back and sides of her head, upper and lower back, holding her hands.
Don't go to the 'naughty' places, or at least, don't go there imediatly.
Well, that's what I came up with on the top of my hat, there's more but I'm not going to type this up for hours :p
And, again, these ar just guidlines. The most important part is to be aware of the girl, don't do your routine but change accordingly how she reacts. If she holds you very tightly, kisses very passionty, you're doing great!
Well, good luck to your son, and may the force be with him