I don't suggest the following for your group (though I do suggest they make up their own verses to add to the traditional ones) but I've heard risque verses such as

Everybody asks her did she come (2x)
A thing they wouldn't have to mention if they only paid attention
Every body asks her did she come

She's got a lovely titty
lating smile (2)
She's got a lovely titti-, a lovely titti-
A lovely tillilating smile

She's got a lovely bottom
set of teeth .....

Oh ye canna push yer granny off the bus (2x)
Oh ye canna push yer granny for she's your mammy's mammy
Oh ye canna push yer granny off the bus

Saying I will if you will, so will I (2x)
I will if you will, I will if you will,
I will if you will, so will I