Welcome to col
This really is NORMAL puppy behaviour and punishing a pup (no cuddles/chilli pepper)for being normal is a bit cruel
As far as hes concerned hes playing. Thats how he would play with his litter mates and mum. The only difference would be that mum would soon put him in his place by nipping back. Also they have started the teething proccess and biting and chewing is an important part of this
I know its painful and frustrating, Ive been there myself as have most of us who post to the forums. I spent the first 4 months in shorts so the little sod couldnt hang of my legs and my arms were a mass of little bruises and scratches. Some one else has posted to this thread how they had to wear gloves when they wanted to handle their pup.
The way most of us get through this stage is with time outs and ouchies, and praise for when they are biting their own toys rather then you.
When you are playing/cuddling with him have a toy at hand. If he starts to bite, give him the toy and if he chews that praise him. If he carries on biting then put him out of the room, somewhere safe, for a couple of minutes. If he whinges and whines, wait for that nanno second hes quiet before you let him back in. You will have to repeat this time and time again (he might be spending more time shut out then in with you playing for a few days) till he learns to associate biting with the end of fun.
Another thing to try is the loud sharp OUCH when he nips. It has to be sharp enough to attract his attention then do the put out of the room.
If you dont have a "safe place" to put him (never use his crate) the just putting him down on the floor and ignoring him (no eye contact) will have the same effect.
As for humping all pups do this - excitement mainly - just discourage it by removing him from your arm or leg with a firm no.
Please dont stop handling him. They need to get used to being handled else you will have a nightmare on your hands when you try to groom him, check ears teeth etc and its an important part of the bonding process
This stage seems to go on forever but by time hes six months and his teeth are through it will end
Hope that helps some