This has happened to a lot of us: as you wrap something, you need to hold down the wrapping paper with one hand and get some tape with the other. The problem is that with those small plastic tape dispensers, this is next to impossible. The job is made much easier with a weighted tape dispenser, which only requires one hand to use. Some even hold two types of tape: the regular narrow kind, and wide packing tape.
Weighted tape dispenser:
Weighted tape dispenser pictured: Officemate Recycled 2-In-1 Heavy Duty Tape Dispenser, Black (96690)