Here are some of the questions / comments I've heard asked from females:
What kind of exercises should I be doing for slimming my thighs if squats and lunges are making them bigger?
I am a female and I work out – what can I do for my thighs enclosed squats? I do not want them to get larger!
The fact of the matter is that there is not much that you can change about your muscle makeup (excluding surgery). You can either grow larger or shrink. Many people misunderstood what muscle toning is. What it really comes down to is you are losing body fat which in turn will help you see your muscles as you get to a lower body fat percentage. No matter your sex or goals, you'll be primarily be doing the same exercises and training methods. The only difference is in how much weight you use, how many reps, the type of sets you do and finally how many calories you take in (more if you're building muscle, less if you're trying to lose fat).
If you do squats or lunges without adding weight or with low weight, you will always reach a point where your muscles will not grow larger. If you want your thighs to lose fat or to look more 'toned' than low weight and higher reps is the way to go. Your thigh muscle will grow slightly thicker and stronger.
So in the end, it's not the squats or lunges which are making your thighs look bulkier but instead the way you are performing your exercise. Remember to do cardio (look at HIIT) and to squat / lunge with minimal weight.