tvastram—the demon Vrtra (son of Tvasta) SB 3.19.25
tvastram—to the son of Tvasta SB 6.7.26
tvastram—the demon Vrtrasura, son of Tvasta SB 6.9.44
tvastram—meant for the demigod known as Tvasta SB 6.14.27
tvastram—performed by Tvasta SB 8.11.35
Can't find any compound Sanskrit words containing tvastram.