You paused for a minute. What would Mistress Liza want you to pick? You considered. She would probably want you to choose the handjob. It was easily the least pleasurable of the two, and she would like that. It would give her - Liza, not necessarily Nikki - to deny you the pleasure of human skin-to-skin contact. And it would be much easier for her to tease you endlessly before allowing you to cum. Also, it would allow her to maintain an air of dominance over you. Sucking your dick would put you in a position of power. She would be servicing you to orgasm, whereas with a handjob she would just be allowing you to orgasm. Liza would want you to submit to her fully, and aside from refusing any orgasm at all, choosing handjob would be the most submissive answer you could give.