Don't blend, it'll come right off. By tapping, you're pressing the foundation right where you need it. The culprit could be your sponge. Sponges are great for absorbing, picking up, erasing. It all goes into the sponge, and not on your face, especially if you use those 'go on like water' foundations.
Sponges are great for heavy duty cream bases, stick foundations, and oil-based foundations.
You get better control over those products. Otherwise, use sponges only to blend edges, take off too much product, or erase a product completely. Use your sponge to get creative with your foundations. Apply a dab of loose powder on the sponge first, then foundation, then apply. The loose powder will thicken up your base.