If he's wearing a condom (and I'm glad he is!) you probably won't know when he's ejaculating, unless it breaks and then that is a problem! Chances are he'll let you know though by any changes in his rhythm or verbal indicators.
My wife says she can feel the throbbing also depending on the position we're in. She says she knows when I've ejaculated also, says she can feel it, but she's been wrong before. I think she can tell really from my other body reactions. I also think you can feel the heartbeat because I'm not as tense down there as I was before the orgasm. But I'm just guessing here. <IMG SRC="http://www.healthboards.com/ubb/smile.gif">
Ok thanx people. Yeah I do try to focus on his verbal changes and breathing etc. He doesn't "say" much but the slowing down is usually an indicator. BUT sometimes I dont know whether he's slowing because he's come or because he hasn't got anymore energy.
My penis throbs uncontrollably when I orgasm, and it continues to spasm for about a minute afterwards too. So women always know when I orgasm, because they can feel my penis spasming. I know that not all guys do this though.