Sorry this may sound really daft, but I am wondering whether anyone could explain what classes as soft g/g?
Depends who is defining it. It could mean anything from just innocent posing together, to pretty explicit touching and stuff, stopping just short of penetrating each other with tongues/fingers/toys etc (hard G/G)
The bottom line is that its whatever you and the other parties decide it is, so set the boundaries and definitions before you agree to anything.
PeterH gives guidance on what most in the porn industry consider to be Soft G/G on his website:-
Before going there be prepared to see more than two bestest friends cuddling.