I have also forced my students to suck and swallow my cum, saying "As a keepsake..." to my students before they graduated. Well, my impression is... "It just feels so good!!" It can be summed up as "fellatio", but fellatio is a very deep subject. If there are 15 people, there are 15 different ways to suck. Ah!! I can generalize it as "high school girls' slurping blowjobs feel so good♪"