Taking Care Of My Young Man

I was looking after my grandson for a few hours the other week and went to check on him and seen him wanking off on his bed.i kept peaking till he jizzed over his stomach, afterwards i sneaked back downstairs and couldn't believe i just watched my 15 year old grandson cum.when he came downstairs i found it hard not to look at his shorts and see his dick bouncing around,it got me thinking the times when he's been at my place and my underwear has been moved so it was my chance to mention it to him, once i did it changed everything between us.he confessed that he uses my underwear to wank with and all that talk was making his dick hard again.I called him over not saying why and when he was in front of me i yanked down his shorts,his dick smacked me in the face i looked up at him and took hold of his dick, wanking away the horny devil said he would rather fuck me and before i could answer him he tells me it's okay we have plenty of time,I was wanking him off so why not go all the way,I was laying back with my legs spread wide and my hungry pussy just waiting for him to fill it,like a newbie he just pushed it in and started bucking as he head fell on my chest,that might of been the quickest anyone has ejaculated with me.i cuddled him just saying it happens to everyone when he starts to move he's back at it slamming his dick in and out of me,that's what i wanted in the first place,not sure how long it was before he cum again but i only had enough time to get my knickers on before my daughter walked in,that would have been hard to explain if she caught her son with his dick in me.