I don't have many of these problems with my tiel, but being the only care taker for my Ekkie in my family, I have had similar problems with him. Unfortunately he sees me as his 'object of affection', Occasionally throughout the year he does the old smelly regurgitation and snuggles bit - although I'm flattered - mentally, for him its not very healthy (nor very nice for me). I have turned to calmly returning him to his cage when he starts this sort of behavior. Luckily Eddie is not really a biting bird, but he definitely shows his stress and frustration by thrashing his toys around and grumbling.
Ways to avoid this behaviour:
I can definitely vouch for moving the cage as an option of distraction from this behaviour - even just to the other side of the room. Or even add some extra toys to the cage - mix up his environment (not to the point of stress though). Once you get things going training helps avoid this behaviour too. The main thing as mentioned in the article is to avoid touching areas like their back. AD is also correct to say covering their cages will make a difference. For the first time in a while I was out working really late last night and no one covered Eddie up at his bed time. He only got about 6 hours good sleep as I had to leave early this morning. But boy he was very grumpy and very loud when I woke him up - he even gave me a tiny nip which he very, VERY rarely does. IMO prevention is definitely better than intervention with this behaviour, intervention just stresses them out.
In your situation - If you find that sexual maturity is the problem, then I would start with covering the gage like AD said and going from there.