limp winnie?

Okay lol. so title says it all... we woke up today and the feeling up began. one thing led to another and we were doing it. he was in deep so i began to grind on him for a little, stopped then he continued. a little slower. after like 2 minutes i was like 🤔🤔🤔??? are you soft?? he said "i guess a little bit. when you were grinding me i was about to cum but i didnt want it to be so short so i stopped myself. idk if that messed me up". can this happen??? or did it just go limp? he's 21 so im like wth 😐. your ideas please lol!! first time this happens.