Disclaimer: I own nothing that has to do with Steven Universe or any other cartoon shows.
Dipper's Office
Mabel is in her brother's office at the new Avengers Tower in New York, working on some plans on a touch screen. She is sitting on a stool by a table, so distracted by her work that she doesn't hear someone enter the room behind her.
The figure quietly comes closer to Mabel and suddenly grabs her from behind. She lets out a loud shriek, and the figure bursts out laughing, revealing the figure to be Steven.
Mabel is in shock, trying to get her breathing under control, "Oh my god, Steven." She holds her left hand on her chest as the other holds Steven's arm that's around her. Steven continues to laugh, his forehead resting on Mabel's left shoulder.
Steven lifts his head after a couple of moments, not laughing as much as he hugs her tightly from behind, "I'm sorry, honey." He places his hand over Mabel's left hand, still on her chest, trying to calm her heart rate. After a minute, they both calm down, and Steven kisses Mabel's left temple and cheek as he leans down and looks at what she's working on, "What are you working on?"
Mabel laces their fingers that are on her chest and answers Steven as she leans back onto him, "Just some renovations for the company and some other stuff Dipper wanted me to look at. Why?" She looks up at Steven curiously.
Steven leans down and kisses Mabel for a few seconds before pulling away a bit. Against her lips, he says, "Because I think you need a break for a little while." He turns Mabel around to face him, standing between her legs as he wraps his arms around her.
Mabel smiles a bit and whispers against Steven's lips, "I could use a long break." She wraps her arms around Steven's neck and kisses him passionately, and Steven pulls her closer.
Mabel reaches her right hand down and presses a button on a touch keyboard, locking the doors and closing the blinds to cover the windows so they don't have any interruptions while they're on their 'break'.