stamina
1. Length of time one lasts in a sexual encounter before climaxing. Additionally, number of successive copulations or climaxes one can achieve.

2. Plural of stamen, which technically is also sexual.
I always get dumped because I lack stamina in bed.

In Carmina 32, Catullus promises his girl 7 successive copulations -- he must have a lot of stamina.

I wonder how much stamina stamina have during pollination. (Talk about the birds and the bees....)