a gerund (n.) and/or particial phrase (adj.), as a gerund phrase, the act of sliding your big thick paw down behind her waistband, down and behind her panties (or thong if she wears one), and into her furbush at the base of the magic triangle, so you can finger fuck her silly at the movies, in her bedroom (while her parents aren't home from work yet), or in the backseat or your Lincoln Continental at the drive-in theater on Saturday night. As a participial phrase, the description of an famous male act as he works on his female love object, trying to get the foreplay going, hopefully, leading to better, harder sex like fucking yadda yadda and more fucking yadda double yadda.
EX: As a gerund phrase: "Gettin' inside her panties was harder than climbing Mt. Everest in your birthday suit in the middle of winter."
As a participial phrse: "Gettin' inside her panties quickly, I took a deep breath and hoped for the best of all possible worlds."