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