To feel someone cum in you is also much more powerfull if you have eye-contact when you get fucked or give a give a blowjob having eye contact with your sexpartner. To my opinion having eyecontact is the stage just before you could know what somebody is thinking or feeling in his brain. With having eyecontact there is apart of the physical connection of the coitus being in contact in each others body and exchange biological stuf as fluids, DNA and other chemicals you also make an even more intimate connection on a more psychological and emotional level because by looking at each other you also not only act or undergo the action but you as a bottom you give the permission to the top that he cums in you, you let him cum in you and you accept and keep his cum in you what to my feeling and opinion is the ultimate level of being bred a part of getting pregnant. For me it is the ultimate surrender and giving somebody almost full power and dominance over your body and mind for a part.