To be "slow on the boner" is to suffer from temporary erectile dysfunction at inconvenient times, such as pre-coitus. Less commonly, the term is also applied to the refractory period.
"I was ready to go ham, but I was slow on the boner so I decided to go down on her first."
The ability girls and women have developed to hold several items at once in one hand. The skill has been developed due to the lack of pockets in women's clothing.
I thought she'd need multiple trips to carry her phone, keys, wallet, and Starbucks to her car since she needed the other hand to open the door, but she used her impressive girl grip to carry everything in one hand.