The generations explained...

P- is a purebred dog. When discussing Whoodles the purebred dog  would be the Poodle and/or the Soft Coated Wheaten Terrier. 

F1- is a mix of 100% Soft Coated Wheaten Terrier and 100% Poodle. Resulting in a Whoodle. 

P + P = F1

F1B- is a puppy that is a result of a Whoodle that has been bred with either a purebred Poodle or a purebred Wheaten. 

F1 + P = F1B

F2- is a puppy that is a result of breeding one Whoodle to another. 

F1 + F1 = F2

F2B-  is a puppy that is the result of a F1 Whoodle being bred to a F1B Whoodle. 

F1 + F1B = F2B

F3- is a puppy that is the result of breeding a F2 Whoodle to another F2 Whoodle. 

F2 + F2 = F3