slips vs. fwd slips
FAA Airplane Flying Handbook has a completely useless illustration in it for differentiating slips from forward slips. They are separate, different techniques with enough similarities to be confusing. One illustration is just the other illustration turned slightly sideways (check it out). I recommend asking local experts what the difference is between them, how they work, when and why to use them. You could also study the problem using a toy airplane and do them in a flight sim or in the air. A good flight sim can show you that certain aircraft must be landed using sideslips if there are crosswinds present (tailwheels). We also had a thread on this subject here earlier this year.