I should warn you, it's only a 5 lined song but requires a bit of an intro in order to explain the actions - you need to be able to sing and clap at the same time (always difficult for boys to do).
This song should be sung with a partner who is clapping hands with yours:
Position 1: Face your partner
Position 2: left palm down, right palm up (clap together)
Position 3: right palm down, left palm up (clap together)
Position 4: palms push out (clap together)
Position 5: clap your hands together
Repeat 2-5 until you get a bum-bum-bum and you repeat Position 4 three times here and then continue.
So, the song goes like this:
Under the bramble bush is under the sea (bum-bum-bum)
True love to you my darling true love for me
I will get married
And raise a family
Under the old bramble tree (bum-bum-bum-bum)
Oh yes, At the lines 'I will get married & raise a family' you only do position 2 & 3. Sounds complicated but it's easy.
It was a playground classic, doesn't make any sense whatsoever, but who cares - I can still do it now, if you want to do it? but if you're crap it doesn't work.