Should i "do it" at his moms house or is it disrespectful?

ok so my boyfriend & i have sex but never at his moms house...he invited me to come over next week so we can have sex there. I said i'd come over but I'm not sure about the sex part....his mom is ALWAYS there but she doesn't go in his room. that's why he's 15 & has f*cked 5 girls at his house with his mom being home & I've only had sex with him. That's kinda why I haven't layed on his bed too....but I really miss being intimate with him so Part of me says "do it because you barely get the chance to" & another part says "don't do it that's disrespectful to his mom and Don't be the 6th girl to be in his bed".....what do you think I should do?? (Yes trey songz....this IS too "unusual" for me) lol =P